Best plants
Foliage is the easy part; flowers indoors take the right light and a little patience. These are the flowering species in our library, each with the light and care it needs to actually bloom.
How this list is built: plants in our library categorised as flowering houseplants— filtered from Growli's structured plant-care library, not hand-picked, so it stays consistent and checkable.
| Plant | Light | Water | Pets |
|---|---|---|---|
| 3D Spider Mix Osteospermum | Direct sun (at least 4-6 hours) | When the top 3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Abelia 'Edward Goucher' | Direct sun (at least 4-6 hours) | Water weekly while establishing; mature plants are drought-tolerant and need water only in prolonged dry weather | Mildly toxic to pets |
| Abelia 'Kaleidoscope' | Direct sun (at least 4-6 hours) | Weekly during establishment, then only in extended drought | Mildly toxic to pets |
| Abelia 'Rose Creek' | Direct sun (at least 4-6 hours) | Weekly while establishing, then occasional deep watering in drought | Mildly toxic to pets |
| Abelia chinensis | Direct sun (at least 4-6 hours) | Weekly through the first season, then mainly during dry spells | Mildly toxic to pets |
| Abelia x grandiflora | Direct sun (at least 4-6 hours) | Weekly deep soak in the first season, then only during prolonged dry spells once established | Mildly toxic to pets |
| Abiqua Drinking Gourd Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Accent Scarlet Busy Lizzie | Medium indirect light (a couple of metres from a window) | Keep the compost evenly moist; typically water every 1-3 days in warm weather as plants wilt quickly in dry conditions | Mildly toxic to pets |
| Acer capillipes | Bright indirect light (just back from a sunny window) | Water deeply weekly while establishing; supplement in summer droughts | Pet-safe |
| Acer griseum | Direct sun (at least 4-6 hours) | Water deeply weekly while establishing; supplement in summer droughts | Pet-safe |
| Acer japonicum 'Aconitifolium' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water deeply in dry spells | Pet-safe |
| Acer palmatum 'Atropurpureum' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply through dry weather | Pet-safe |
| Acer palmatum 'Butterfly' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry; keep evenly moist, more often in pots and heat | Pet-safe |
| Acer palmatum 'Dissectum' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry; keep evenly moist, more often in pots and heat | Pet-safe |
| Acer palmatum 'Garnet' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry; keep evenly moist, more often in pots and heat | Pet-safe |
| Acer palmatum 'Orangeola' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry; keep evenly moist, more often in containers and heat | Pet-safe |
| Acer rubrum | Direct sun (at least 4-6 hours) | Deep soak weekly for the first two seasons; established trees rely on rainfall | Mildly toxic to pets |
| Acer rubrum 'Autumn Blaze' | Direct sun (at least 4-6 hours) | Weekly while establishing; deep watering in droughts thereafter | Pet-safe |
| Acer rubrum 'October Glory' | Direct sun (at least 4-6 hours) | Weekly while establishing; deep watering in dry spells thereafter | Pet-safe |
| Achillea 'Terracotta' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry; roughly every 7-10 days while establishing, rarely once mature | Toxic to pets |
| Achillea millefolium 'Cerise Queen' | Direct sun (at least 4-6 hours) | When the top few centimeters of soil are dry, about every 7-14 days | Mildly toxic to pets |
| Achillea ptarmica 'The Pearl' | Direct sun (at least 4-6 hours) | When the top few cm of soil dry out; roughly weekly, more in heat | Toxic to pets |
| Achimenes | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is dry, every 4-6 days in summer | Mildly toxic to pets |
| Achimenes 'Cascade Violet Night' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, roughly every 4-6 days | Pet-safe |
| Achimenes 'Peach Blossom' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, roughly every 4-6 days | Pet-safe |
| Achimenes 'Tarantella' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, roughly every 4-6 days | Pet-safe |
| Achimenes erecta | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, roughly every 4-6 days | Pet-safe |
| Achimenes grandiflora | Bright indirect light (just back from a sunny window) | Keep evenly moist while in growth, roughly every 4-6 days | Pet-safe |
| Adagio Maiden Grass | Direct sun (at least 4-6 hours) | Weekly in the first year, then mostly rainfall except in drought | Mildly toxic to pets |
| Adagio Maiden Grass | Direct sun (at least 4-6 hours) | Weekly for the first season; every 2–3 weeks once established | Pet-safe |
| Adiantum venustum | Medium indirect light (a couple of metres from a window) | When the top 1-2 cm of soil begins to dry, roughly every 4-6 days | Pet-safe |
| Adolphe Audusson camellia | Bright indirect light (just back from a sunny window) | Regular; keep consistently moist, especially during bud set | Mildly toxic to pets |
| Adolphe Audusson Camellia | Bright indirect light (just back from a sunny window) | Every 5-7 days in the growing season; keep consistently moist but not waterlogged | Pet-safe |
| Adriatic Bellflower | Bright indirect light (just back from a sunny window) | Weekly during spring and summer; minimal in winter | Pet-safe |
| Aerangis biloba | Bright indirect light (just back from a sunny window) | Every 1-3 days when mounted; every 3-5 days in a small basket, kept lightly moist | Pet-safe |
| Aerangis luteoalba | Bright indirect light (just back from a sunny window) | Every 1-3 days when mounted; every 3-5 days in a small basket, keeping it lightly moist | Pet-safe |
| Aeschynanthus 'Black Pagoda' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Aeschynanthus 'Mona Lisa' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Aeschynanthus 'Rasta' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Aeschynanthus lobbianus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Aeschynanthus marmoratus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Aeschynanthus pulcher | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Aeschynanthus radicans 'Curly Q' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Pet-safe |
| Aeschynanthus speciosus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 4-8 days in growth | Pet-safe |
| Aeschynanthus tricolor | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days | Pet-safe |
| Aesculifolia Rodgersia | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply 1-2 times weekly, more in heat | Mildly toxic to pets |
| Aesculus × carnea 'Briotii' | Direct sun (at least 4-6 hours) | Water young trees weekly to establish, then rely on rainfall | Toxic to pets |
| Aesculus flava | Direct sun (at least 4-6 hours) | Deep watering every 7-10 days through the first two or three growing seasons; established trees rarely need irrigation | Toxic to pets |
| Aesculus hippocastanum | Direct sun (at least 4-6 hours) | Water young trees weekly to establish, then rely on rainfall | Toxic to pets |
| Afghan Iris | Direct sun (at least 4-6 hours) | Moderate in late winter to late spring; bone dry from midsummer to early autumn | Toxic to pets |
| African Cornflag | Direct sun (at least 4-6 hours) | Weekly during the winter-spring growing season; none in summer dormancy | Mildly toxic to pets |
| African Crossandra | Bright indirect light (just back from a sunny window) | Every 5–7 days in the growing season, reducing to every 10–14 days in winter | Pet-safe |
| African feather grass | Direct sun (at least 4-6 hours) | Every 1–2 weeks once established; more frequently when newly planted | Pet-safe |
| African marigold | Direct sun (at least 4-6 hours) | Once or twice weekly; allow top 2–3 cm of soil to dry between waterings | Mildly toxic to pets |
| African Marigold 'Crackerjack' | Direct sun (at least 4-6 hours) | When top 3-4 cm of soil is dry, about every 4-7 days | Mildly toxic to pets |
| African Tamarisk | Direct sun (at least 4-6 hours) | Low once established; moderate during establishment | Pet-safe |
| African violet | Medium indirect light (a couple of metres from a window) | When the top of the soil feels just dry, every 5-7 days | Pet-safe |
| African Violet 'Blue Nile' | Bright indirect light (just back from a sunny window) | When the top of the soil feels barely dry, roughly every 5-7 days | Pet-safe |
| African Violet 'Optimara EverFloris' | Bright indirect light (just back from a sunny window) | When the top of the soil feels just dry, about every 5-7 days | Pet-safe |
| African Violet 'Optimara Little Maya' | Bright indirect light (just back from a sunny window) | When the top of the soil feels barely dry, roughly every 5-7 days | Pet-safe |
| African Violet 'Optimara' | Bright indirect light (just back from a sunny window) | When the top of the soil feels barely dry, roughly every 5-7 days | Pet-safe |
| African Violet 'Rob's Boolaroo' | Bright indirect light (just back from a sunny window) | When the top of the soil feels barely dry, roughly every 5-7 days | Pet-safe |
| African Yellowwood | Bright indirect light (just back from a sunny window) | When the top few cm of soil dry, roughly weekly while establishing | Toxic to pets |
| Agapanthus 'Headbourne Hybrids' | Direct sun (at least 4-6 hours) | Weekly through spring and summer growth; reduce sharply once foliage dies back in autumn | Mildly toxic to pets |
| Agapanthus 'Midnight Blue' | Direct sun (at least 4-6 hours) | Weekly while in growth and bud, more in containers; reduce as foliage dies back | Mildly toxic to pets |
| Agapanthus 'Navy Blue' | Direct sun (at least 4-6 hours) | Weekly during active growth and budding; taper off as leaves die back in autumn | Mildly toxic to pets |
| Agapanthus africanus 'Albus' | Direct sun (at least 4-6 hours) | Water regularly, roughly twice weekly in hot weather while growing; keep just moist in winter | Mildly toxic to pets |
| Agapanthus inapertus subsp. pendulus | Direct sun (at least 4-6 hours) | Weekly during active growth and budding; taper off as foliage dies back in autumn | Mildly toxic to pets |
| Agastache 'Black Adder' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-14 days once established | Mildly toxic to pets |
| Agastache 'Blue Fortune' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Agastache 'Kudos Coral' | Direct sun (at least 4-6 hours) | Water deeply during the first season while establishing, then only in prolonged drought once mature | Mildly toxic to pets |
| Agave-Leaved Sea Holly | Direct sun (at least 4-6 hours) | Low — occasional deep watering during the first season, minimal thereafter | Pet-safe |
| Ageratum houstonianum 'Artist Blue' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days | Toxic to pets |
| Ageratum houstonianum 'Blue Horizon' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days | Toxic to pets |
| Agnes Rose | Direct sun (at least 4-6 hours) | Deep watering once a week, more in drought or first season | Pet-safe |
| Akebia quinata | Bright indirect light (just back from a sunny window) | When the top 4-5 cm of soil dries, about every 7-10 days while establishing | Mildly toxic to pets |
| Akebia trifoliata | Bright indirect light (just back from a sunny window) | When the top 4-5 cm of soil dries, about every 7-10 days while establishing | Mildly toxic to pets |
| Alan Fradd Rock Rose | Direct sun (at least 4-6 hours) | Establish with deep, infrequent waterings in the first season; drought-tolerant once established and needs no irrigation in typical UK summers. | Mildly toxic to pets |
| Alaska Mix Nasturtium | Direct sun (at least 4-6 hours) | When the top 3–5 cm of soil is dry, roughly every 7 days | Mildly toxic to pets |
| Albert's Gold tree heath | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks in summer once established | Pet-safe |
| Albion Black Pod nigella | Direct sun (at least 4-6 hours) | Weekly or as needed | Mildly toxic to pets |
| Albizia julibrissin | Direct sun (at least 4-6 hours) | Water weekly during establishment, then only in extended drought | Mildly toxic to pets |
| Albizia julibrissin 'Rosea' | Direct sun (at least 4-6 hours) | Water weekly while establishing, then only in prolonged drought | Mildly toxic to pets |
| Alchemilla mollis | Bright indirect light (just back from a sunny window) | Water in dry spells; established plants are drought-tolerant and need watering only occasionally | Mildly toxic to pets |
| Alerce | Bright indirect light (just back from a sunny window) | Keep consistently moist at all times; water deeply during any dry period and never allow drought | Mildly toxic to pets |
| Aleutian Mountain Heath | Bright indirect light (just back from a sunny window) | Keep consistently moist; water whenever the top 2–3 cm of soil begins to dry. | Mildly toxic to pets |
| Aleutian mountain heather | Direct sun (at least 4-6 hours) | Consistently moist throughout the growing season; reduce slightly in winter dormancy | Mildly toxic to pets |
| Algerian Fir | Direct sun (at least 4-6 hours) | Low to moderate; highly drought-tolerant once established | Pet-safe |
| Alisma plantago-aquatica | Direct sun (at least 4-6 hours) | Constantly wet; shallow margin | Mildly toxic to pets |
| Allegheny Spurge | Low light (north window or shaded room) | Weekly during the first 1–2 growing seasons; every 2–3 weeks once established | Mildly toxic to pets |
| Allioni's Primrose | Bright indirect light (just back from a sunny window) | Moderately during spring and summer; very sparingly in winter | Toxic to pets |
| Allium 'Firmament' | Direct sun (at least 4-6 hours) | Water at planting and during spring growth; keep dry in summer dormancy | Toxic to pets |
| Allium 'Gladiator' | Direct sun (at least 4-6 hours) | Water during spring growth; keep dry in summer dormancy, every 2-3 weeks at most if drought-stressed | Toxic to pets |
| Allium 'Globemaster' | Direct sun (at least 4-6 hours) | Water during spring growth; keep dry through summer dormancy, every 2-3 weeks at most if drought-stressed | Toxic to pets |
| Allium 'Hair' | Direct sun (at least 4-6 hours) | Water at planting then only in prolonged spring drought; keep dry once dormant | Toxic to pets |
| Allium 'Mount Everest' | Direct sun (at least 4-6 hours) | Water in spring growth; keep dry over summer dormancy, every 2-3 weeks at most if very dry | Toxic to pets |
| Allium 'Purple Sensation' | Direct sun (at least 4-6 hours) | Water during active spring growth only; otherwise minimal, every 2-3 weeks if dry | Toxic to pets |
| Allium schubertii | Direct sun (at least 4-6 hours) | Water lightly in spring growth; keep very dry through summer dormancy, rarely if ever in summer | Toxic to pets |
| Alma Potschke aster | Direct sun (at least 4-6 hours) | Weekly during the growing season; reduce after flowering | Pet-safe |
| Alphonse Karr Bamboo | Direct sun (at least 4-6 hours) | Regularly during summer, approximately every 5–7 days; reduce in cooler months as growth slows | Pet-safe |
| Alpine Aster | Direct sun (at least 4-6 hours) | Once per week in dry spells; rainfall usually sufficient when established | Mildly toxic to pets |
| Alpine Azalea | Bright indirect light (just back from a sunny window) | Regular; keep soil moist | Mildly toxic to pets |
| Alpine Balsam | Direct sun (at least 4-6 hours) | Every 7–14 days during growth; reduce after setting seed | Mildly toxic to pets |
| Alpine Bartsia | Bright indirect light (just back from a sunny window) | Keep evenly moist; water regularly to prevent drying out | Mildly toxic to pets |
| Alpine bearberry | Direct sun (at least 4-6 hours) | Moderate; keep soil moist but well-drained; water regularly during dry periods | Pet-safe |
| Alpine Campion | Bright indirect light (just back from a sunny window) | Low to moderate — water during dry spells; ensure good drainage | Mildly toxic to pets |
| Alpine Cinquefoil | Direct sun (at least 4-6 hours) | Every 10–14 days; very drought-tolerant once established | Pet-safe |
| Alpine Clematis | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 10-14 days in the growing season | Toxic to pets |
| Alpine Heron's Bill | Direct sun (at least 4-6 hours) | Low to moderate — allow soil surface to dry between waterings | Mildly toxic to pets |
| Alpine Liverwort | Bright indirect light (just back from a sunny window) | Low to moderate — water when the top centimetre of soil dries | Mildly toxic to pets |
| Alpine Mouse-ear | Direct sun (at least 4-6 hours) | Sparingly — allow soil to dry between waterings; minimal winter moisture | Pet-safe |
| Alpine Pink | Direct sun (at least 4-6 hours) | Low to moderate; water when the top 2 cm of soil are dry | Mildly toxic to pets |
| Alpine Rock Cress | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| Alpine Rock Jasmine | Direct sun (at least 4-6 hours) | Low — allow the top inch of soil to dry between waterings | Mildly toxic to pets |
| Alpine Sea Holly | Direct sun (at least 4-6 hours) | Water during establishment and in extended dry spells; otherwise infrequently | Mildly toxic to pets |
| Alpine Squill | Medium indirect light (a couple of metres from a window) | Water during growth; dry during summer dormancy | Toxic to pets |
| Alpine Toadflax | Direct sun (at least 4-6 hours) | Every 10–14 days in the growing season; minimal in winter. | Mildly toxic to pets |
| Alpine Totara | Direct sun (at least 4-6 hours) | When the top few cm of soil dry out, roughly weekly while establishing | Toxic to pets |
| Alsobia 'San Miguel' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Alsobia dianthiflora | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, roughly every 4-7 days | Pet-safe |
| Altissimo Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the first season; established plants when the top 5 cm of soil is dry | Pet-safe |
| Amaryllis | Bright indirect light (just back from a sunny window) | Sparingly until growth appears, then keep evenly moist | Toxic to pets |
| Amaryllis 'Apple Blossom' | Bright indirect light (just back from a sunny window) | Sparingly until growth starts, then when top 2-3 cm of soil is dry | Toxic to pets |
| Amaryllis 'Christmas Gift' | Bright indirect light (just back from a sunny window) | Sparingly until growth starts, then when top 2-3 cm of soil is dry | Toxic to pets |
| Amaryllis 'Minerva' | Bright indirect light (just back from a sunny window) | Sparingly until growth starts, then when top 2-3 cm of soil is dry | Toxic to pets |
| Amaryllis 'Papilio' | Bright indirect light (just back from a sunny window) | When top 2-3 cm of soil is dry, roughly every 7-10 days in growth | Toxic to pets |
| Amaryllis 'Picotee' | Bright indirect light (just back from a sunny window) | Sparingly until growth starts, then when top 2-3 cm of soil is dry | Toxic to pets |
| Amaryllis 'Red Lion' | Bright indirect light (just back from a sunny window) | Sparingly until growth starts, then when top 2-3 cm of soil is dry | Toxic to pets |
| Amazon Mist Sedge | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply once or twice weekly in heat, less in cool weather | Mildly toxic to pets |
| Amazon Moonflower Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of substrate is dry, roughly every 7-10 days in the growing season; every 2-3 weeks in a cooler rest period | Pet-safe |
| Amboina Kauri | Direct sun (at least 4-6 hours) | Every 7-10 days when the top few centimetres of soil are dry | Mildly toxic to pets |
| Amelanchier × grandiflora 'Robin Hill' | Direct sun (at least 4-6 hours) | Weekly deep watering through the first two seasons; established trees need water only in prolonged drought | Mildly toxic to pets |
| Amelanchier canadensis | Direct sun (at least 4-6 hours) | Weekly while establishing; prefers consistently moist soil | Mildly toxic to pets |
| America Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly while establishing; mature plants when the top few centimetres of soil dry out | Pet-safe |
| American alumroot | Medium indirect light (a couple of metres from a window) | Once or twice per week; reduce in winter | Pet-safe |
| American Basswood | Bright indirect light (just back from a sunny window) | Weekly during establishment; less once mature | Pet-safe |
| American Bittersweet | Bright indirect light (just back from a sunny window) | Water deeply once a week during the first two growing seasons; established plants are drought-tolerant and need watering only during extended dry periods | Toxic to pets |
| American Elm Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil begins to dry, frequently in summer | Mildly toxic to pets |
| American Holly | Bright indirect light (just back from a sunny window) | Weekly while establishing, then during dry spells | Toxic to pets |
| American Hornbeam | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil approaches dryness, often daily in summer | Mildly toxic to pets |
| American Turk's Cap Lily | Bright indirect light (just back from a sunny window) | Twice weekly; more in dry periods | Toxic to pets |
| American White Water Lily | Direct sun (at least 4-6 hours) | Permanently aquatic — crown submerged 15–60 cm (6–24 in) below water surface | Pet-safe |
| American wisteria | Direct sun (at least 4-6 hours) | Weekly during establishment; drought-tolerant once mature | Toxic to pets |
| American Wood Anemone | Medium indirect light (a couple of metres from a window) | Weekly during active spring growth; none during summer dormancy | Toxic to pets |
| Amethyst Sea Holly | Direct sun (at least 4-6 hours) | Low — water sparingly once established | Mildly toxic to pets |
| Amphibious Bistort | Direct sun (at least 4-6 hours) | Permanent wet soil or shallow water — no irrigation needed once established | Mildly toxic to pets |
| Andean Silver-Leaf Sage | Direct sun (at least 4-6 hours) | Allow soil to dry 2–3 cm between waterings | Mildly toxic to pets |
| Anderson's Holly Fern | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Andorra Compact Juniper | Direct sun (at least 4-6 hours) | Every 7-10 days in the first season, then sparingly | Mildly toxic to pets |
| Anemone × hybrida 'Honorine Jobert' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water deeply weekly in dry spells, more in its first year | Toxic to pets |
| Anemone × hybrida 'Königin Charlotte' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply once a week in dry weather, more while establishing | Toxic to pets |
| Anemone × hybrida 'Pamina' | Bright indirect light (just back from a sunny window) | Keep evenly moist; deep weekly watering in dry weather, more while establishing | Toxic to pets |
| Anemone × hybrida 'September Charm' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry; keep evenly moist, especially while establishing | Toxic to pets |
| Anemone coronaria 'Hollandia' | Direct sun (at least 4-6 hours) | Keep soil evenly moist during active growth and flowering; every 5-7 days if no rain | Toxic to pets |
| Anemone coronaria 'Meron Violet' | Direct sun (at least 4-6 hours) | Keep soil evenly moist during active growth and flowering; reduce as foliage yellows toward dormancy | Toxic to pets |
| Anemone coronaria 'Mr. Fokker' | Direct sun (at least 4-6 hours) | Keep soil evenly moist through growth and flowering; reduce as foliage yellows toward dormancy | Toxic to pets |
| Anemone coronaria 'The Bride' | Direct sun (at least 4-6 hours) | Keep soil evenly moist through growth and flowering; reduce as foliage yellows toward dormancy | Toxic to pets |
| Anemone hupehensis 'Hadspen Abundance' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water deeply weekly in dry spells and more during establishment | Toxic to pets |
| Angel Face Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly | Pet-safe |
| Angel Wing Begonia | Bright indirect light (just back from a sunny window) | When the top 1-2 inches (2.5-5 cm) of soil feel dry | Toxic to pets |
| Angel Wing Begonia 'Lucerna' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, about every 7-10 days | Toxic to pets |
| Angel's Fishing Rod | Direct sun (at least 4-6 hours) | Regular during spring and summer; reduced in winter | Mildly toxic to pets |
| Angel's Tears Daffodil | Direct sun (at least 4-6 hours) | Low; water during active growth, dry summer dormancy | Toxic to pets |
| Angel's Tears Daffodil | Direct sun (at least 4-6 hours) | Once per week during active spring growth; dry dormancy required in summer | Toxic to pets |
| Angel's Tears Narcissus | Direct sun (at least 4-6 hours) | Moderate during growth; dry during summer dormancy | Toxic to pets |
| Angel's Trumpet | Direct sun (at least 4-6 hours) | Every 1-3 days in peak summer growth; far less when dormant or overwintering | Toxic to pets |
| Angel's Trumpet Hybrid | Direct sun (at least 4-6 hours) | Every 2–4 days in summer (keep consistently moist) | Toxic to pets |
| Angelina Stonecrop | Direct sun (at least 4-6 hours) | When soil is fully dry, roughly every 10-14 days in summer; little to none in winter | Pet-safe |
| Angelique Double Tulip | Direct sun (at least 4-6 hours) | Water at planting; minimal supplemental irrigation during growth; dry during dormancy | Toxic to pets |
| Angelonia angustifolia 'Archangel White' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Mildly toxic to pets |
| Angelonia angustifolia 'Serenita Raspberry' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Mildly toxic to pets |
| Angraecum distichum | Bright indirect light (just back from a sunny window) | Keep evenly moist; water roughly every 2-4 days when mounted, or when the bark surface just begins to dry | Pet-safe |
| Anguloa clowesii | Bright indirect light (just back from a sunny window) | Every 5-7 days in active summer growth; taper to roughly every 2-3 weeks once leaves yellow and drop | Mildly toxic to pets |
| Anise-scented Sage | Bright indirect light (just back from a sunny window) | Regular throughout the growing season | Pet-safe |
| Ann Folkard Cranesbill | Bright indirect light (just back from a sunny window) | Moderate; water during dry spells | Mildly toxic to pets |
| Anne Thomson Cranesbill | Bright indirect light (just back from a sunny window) | Moderate; water during dry spells | Mildly toxic to pets |
| Annual baby's breath | Direct sun (at least 4-6 hours) | Once weekly; allow the soil to dry slightly between waterings | Mildly toxic to pets |
| Annual Clary | Direct sun (at least 4-6 hours) | Every 7–10 days | Mildly toxic to pets |
| Annual Phlox | Direct sun (at least 4-6 hours) | Every 5–7 days; keep soil evenly moist but not saturated | Pet-safe |
| Annual Phlox 'Sugar Stars' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 4-7 days | Pet-safe |
| Anthurium | Bright indirect light (just back from a sunny window) | When the top 3 cm of soil is dry, every 5-7 days | Toxic to pets |
| Anthurium 'Black Queen' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Anthurium 'Livium' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days in growth | Toxic to pets |
| Anthurium Andreanum | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days | Toxic to pets |
| Antirrhinum majus 'Chantilly Bronze' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Antirrhinum majus 'Rocket Red' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Antirrhinum majus 'Sonnet Pink' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Antirrhinum majus 'Twinny Peach' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Pet-safe |
| Apache beggarticks | Direct sun (at least 4-6 hours) | Every 3–5 days in containers; every 7–10 days in-ground once established | Mildly toxic to pets |
| Apennine Windflower | Medium indirect light (a couple of metres from a window) | Rainfall usually sufficient in woodland settings; water once per week only during dry springs | Toxic to pets |
| Aponogeton distachyos | Direct sun (at least 4-6 hours) | Permanently submerged; maintain a stable pond water level | Mildly toxic to pets |
| Appalachian Barren Strawberry | Medium indirect light (a couple of metres from a window) | Low to moderate; drought-tolerant once established | Pet-safe |
| Appalachian Blazing Star | Direct sun (at least 4-6 hours) | Every 2 weeks during establishment; essentially rain-fed once mature | Pet-safe |
| Apple Blossom flowering quince | Bright indirect light (just back from a sunny window) | Weekly when establishing; rainfall sufficient for established plants in temperate climates | Mildly toxic to pets |
| Apricot Sprite Hyssop | Direct sun (at least 4-6 hours) | Every 7–10 days once established; more frequent in containers | Pet-safe |
| Aptos Blue Redwood | Direct sun (at least 4-6 hours) | Weekly when young; every 1–2 weeks when established | Pet-safe |
| Aptos Blue Redwood | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days in summer | Mildly toxic to pets |
| Aquilegia 'Black Barlow' | Medium indirect light (a couple of metres from a window) | Water when the top 3 cm of soil dries, roughly weekly | Mildly toxic to pets |
| Aquilegia 'Nora Barlow' | Medium indirect light (a couple of metres from a window) | Water when the top 3 cm of soil dries, about weekly | Mildly toxic to pets |
| Arabian Jasmine | Direct sun (at least 4-6 hours) | Keep evenly moist in growth; water when the top 2-3 cm of soil dries, often every 3-5 days in warmth | Pet-safe |
| Arching Spider Orchid | Bright indirect light (just back from a sunny window) | When the medium nears dryness, about every 4-6 days in warm growth | Mildly toxic to pets |
| Arctic Bell-heather | Bright indirect light (just back from a sunny window) | Keep the root zone consistently moist at all times; water before the top 2 cm dries. | Mildly toxic to pets |
| Arendsii astilbe | Medium indirect light (a couple of metres from a window) | 2–3 times per week in summer; weekly otherwise | Pet-safe |
| Argentine Giant Cactus | Direct sun (at least 4-6 hours) | When the soil is dry, about every 1-2 weeks in summer; keep dry in winter | Pet-safe |
| Arisaema consanguineum | Medium indirect light (a couple of metres from a window) | Keep evenly moist during growth, about every 4-7 days; ease off as it dies back | Toxic to pets |
| Arisaema elephas | Medium indirect light (a couple of metres from a window) | Keep evenly moist during growth, about every 4-7 days; reduce as it dies back | Toxic to pets |
| Arisaema flavum | Medium indirect light (a couple of metres from a window) | Keep evenly moist during active growth (spring to late summer); withhold once dormant | Toxic to pets |
| Arisaema griffithii | Medium indirect light (a couple of metres from a window) | Keep evenly moist through growth, roughly every 4-7 days; reduce sharply once foliage yellows | Toxic to pets |
| Arisaema jacquemontii | Bright indirect light (just back from a sunny window) | Keep evenly moist in spring and summer growth; allow to dry as the leaf dies back in late summer | Toxic to pets |
| Arisaema nepenthoides | Bright indirect light (just back from a sunny window) | Keep evenly moist in spring and summer; let it dry as the leaf dies back in late summer | Toxic to pets |
| Arisaema ringens | Medium indirect light (a couple of metres from a window) | Keep evenly moist during growth, about every 4-7 days; reduce as it dies back | Toxic to pets |
| Arisaema serratum | Bright indirect light (just back from a sunny window) | Keep evenly moist through spring and summer; allow drying as the leaf dies back in autumn | Toxic to pets |
| Arisaema speciosum | Medium indirect light (a couple of metres from a window) | Keep evenly moist through growth, about every 4-7 days; reduce as it dies back | Toxic to pets |
| Arisaema tortuosum | Medium indirect light (a couple of metres from a window) | Keep moist through the growing season, about every 4-7 days; reduce as it dies back | Toxic to pets |
| Arizona Cypress | Direct sun (at least 4-6 hours) | Every 1-2 weeks while establishing, then rarely | Mildly toxic to pets |
| Arizona Cypress 'Blue Ice' | Direct sun (at least 4-6 hours) | Every 1-2 weeks while establishing, then rarely | Mildly toxic to pets |
| Arkansas Beardtongue | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Mildly toxic to pets |
| Armand's Clematis | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 10-14 days | Toxic to pets |
| Armenian Speedwell | Direct sun (at least 4-6 hours) | Every 10–14 days during the growing season; little to none in winter. | Pet-safe |
| Aroanian Germander | Direct sun (at least 4-6 hours) | Minimal — once every 3 weeks in summer; dry in winter | Mildly toxic to pets |
| Aromatic Aster | Direct sun (at least 4-6 hours) | Water to establish, then rarely; very drought-tolerant | Pet-safe |
| Aromatic Aster 'Raydon's Favorite' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 10-14 days once established | Mildly toxic to pets |
| Arrow Arum | Bright indirect light (just back from a sunny window) | Permanent shallow flooding — plant in up to 15 cm of water | Toxic to pets |
| Arrowwood Viburnum | Direct sun (at least 4-6 hours) | Weekly when young; established plants tolerate both moist and occasionally dry soil | Pet-safe |
| Arroyo Lupine | Direct sun (at least 4-6 hours) | Low once established; rely on winter rainfall; supplement lightly in February–March during dry years | Toxic to pets |
| Arum Lily | Bright indirect light (just back from a sunny window) | Regularly moist to wet — water every 2–3 days or plant in standing water | Toxic to pets |
| Ashton's Ice Plant | Direct sun (at least 4-6 hours) | When the top 2–3 cm of soil is dry, roughly every 7–14 days during the growing season; minimal in winter | Mildly toxic to pets |
| Ashy Broom | Direct sun (at least 4-6 hours) | Low — water sparingly once established | Toxic to pets |
| Ashy Sunflower | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; very drought-tolerant | Pet-safe |
| Asian Star Jasmine | Medium indirect light (a couple of metres from a window) | Water every 7-10 days during the first growing season; established plants are fairly drought-tolerant and need watering only during prolonged dry periods | Mildly toxic to pets |
| Asphodel Cranesbill | Bright indirect light (just back from a sunny window) | Weekly during the growing season; reduce in autumn | Pet-safe |
| Asplenium platyneuron | Low light (north window or shaded room) | Water when the top 2-3 cm is dry; tolerates short dry spells better than most ferns | Pet-safe |
| Aster 'Alma Potschke' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Aster 'Fellowship' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 7 days | Mildly toxic to pets |
| Aster 'Harrington's Pink' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Aster 'Hella Lacy' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Aster 'Little Carlow' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Aster 'Monte Cassino' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during summer | Mildly toxic to pets |
| Aster 'October Skies' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days once established | Pet-safe |
| Aster 'Professor Kippenburg' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-10 days in summer | Mildly toxic to pets |
| Aster 'Purple Dome' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Aster 'Raydon's Favorite' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days once established | Pet-safe |
| Aster 'Vibrant Dome' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Aster 'Wood's Pink' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 7 days | Mildly toxic to pets |
| Aster × frikartii 'Mönch' | Direct sun (at least 4-6 hours) | Water to establish, then moderately; water in prolonged dry spells | Pet-safe |
| Astilbe 'Bridal Veil' | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply 1-2 times weekly, more in heat | Mildly toxic to pets |
| Astilbe 'Deutschland' | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water every 3-5 days or as needed to prevent the top 2 cm of soil drying out | Pet-safe |
| Astilbe 'Fanal' | Bright indirect light (just back from a sunny window) | Keep soil constantly moist; water every 2-4 days in summer, never letting it dry out | Mildly toxic to pets |
| Astilbe 'Fanal' | Medium indirect light (a couple of metres from a window) | Consistently moist — water whenever the top 2-3 cm of soil begins to dry, roughly every 3-5 days in summer | Pet-safe |
| Astilbe chinensis 'Pumila' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil begins to dry; keep evenly moist, often 2-3 times weekly in heat | Mildly toxic to pets |
| Astilbe simplicifolia 'Sprite' | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply 1-2 times weekly, more in heat | Mildly toxic to pets |
| Athyrium angustum f. rubellum 'Lady in Red' | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist, watering when the top 2-3 cm dries, roughly every 4-6 days | Mildly toxic to pets |
| Athyrium filix-femina 'Frizelliae' | Low light (north window or shaded room) | Keep evenly moist; water every 4-6 days, more in hot weather | Mildly toxic to pets |
| Athyrium filix-femina 'Minutissimum' | Low light (north window or shaded room) | Keep consistently moist; water every 4-6 days, more in heat | Mildly toxic to pets |
| Athyrium niponicum 'Red Beauty' | Low light (north window or shaded room) | Keep evenly moist; water every 4-6 days, more often in heat | Mildly toxic to pets |
| Athyrium niponicum 'Ursula's Red' | Low light (north window or shaded room) | Keep evenly moist; water every 4-6 days, increasing in hot weather | Mildly toxic to pets |
| Athyrium otophorum | Low light (north window or shaded room) | Keep evenly moist; water every 4-6 days, more in heat | Mildly toxic to pets |
| Atlantic White Cedar | Direct sun (at least 4-6 hours) | Constant moisture; tolerates standing water seasonally | Mildly toxic to pets |
| Atlantic Wild Indigo | Direct sun (at least 4-6 hours) | Low once established; water weekly in the first season | Toxic to pets |
| Atlas Cedar | Direct sun (at least 4-6 hours) | Weekly during establishment; very drought-tolerant once established | Mildly toxic to pets |
| Atlas Poppy | Direct sun (at least 4-6 hours) | Once a week in dry spells during active growth; largely drought-tolerant once established | Toxic to pets |
| Aucuba japonica Crotonifolia | Low light (north window or shaded room) | Water to establish, then every 7-14 days in dry spells; less in cool months | Mildly toxic to pets |
| Aucuba japonica Picturata | Low light (north window or shaded room) | When the top 3-5 cm of soil is dry, about weekly while establishing then less often | Mildly toxic to pets |
| Aucuba japonica Rozannie | Low light (north window or shaded room) | When the top 3-5 cm of soil is dry, roughly weekly in the first year then far less once established | Mildly toxic to pets |
| Audray White globe amaranth | Direct sun (at least 4-6 hours) | Every 5–7 days; drought-tolerant once established | Pet-safe |
| Augustine's rhododendron | Bright indirect light (just back from a sunny window) | Every 7–10 days in active growth; reduce in winter | Toxic to pets |
| Aunt Eliza Montbretia | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season; allow to dry back naturally in autumn | Mildly toxic to pets |
| Aureola Japanese Forest Grass | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil feels dry, roughly every 5-7 days in the growing season | Pet-safe |
| Auricula | Bright indirect light (just back from a sunny window) | Moderately in spring and summer; reduce significantly in autumn and winter | Toxic to pets |
| Auricula Primrose | Bright indirect light (just back from a sunny window) | Water when top 2 cm of soil is dry; more frequent in active growth, sparingly in summer | Mildly toxic to pets |
| Autumn Brilliance serviceberry | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once established | Pet-safe |
| Autumn Cascades Tupelo | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once mature | Mildly toxic to pets |
| Autumn Catchfly | Direct sun (at least 4-6 hours) | Every 7–10 days in summer; reduce in winter | Pet-safe |
| Autumn Crocus | Direct sun (at least 4-6 hours) | Low — naturally rainfall-dependent; needs dry summer dormancy | Mildly toxic to pets |
| Autumn Crocus | Bright indirect light (just back from a sunny window) | Relies on natural rainfall; rarely needs supplementary watering | Toxic to pets |
| Autumn Crocus Speciosus | Direct sun (at least 4-6 hours) | Rainfall usually sufficient outdoors; water sparingly once per week only if autumn is exceptionally dry | Mildly toxic to pets |
| Autumn Daffodil | Direct sun (at least 4-6 hours) | Moderate during autumn and spring growth; dry during summer dormancy | Toxic to pets |
| Autumn Gentian | Direct sun (at least 4-6 hours) | Very low — rain-fed only | Mildly toxic to pets |
| Autumn Gold Maidenhair Tree | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days when young | Toxic to pets |
| Autumn heath | Direct sun (at least 4-6 hours) | Fortnightly during establishment; drought-tolerant once established | Pet-safe |
| Autumn Joy Stonecrop | Direct sun (at least 4-6 hours) | Water to establish, then only in prolonged drought — roughly every 10-14 days if newly planted | Mildly toxic to pets |
| Autumn Moor Grass | Direct sun (at least 4-6 hours) | Weekly during the first season; established plants only in prolonged drought | Mildly toxic to pets |
| Autumn Moor Grass | Medium indirect light (a couple of metres from a window) | Every 10-14 days during establishment; drought-tolerant once established | Pet-safe |
| Autumn Pineapple Lily | Direct sun (at least 4-6 hours) | Moderate during growth; reduce after foliage dies back | Toxic to pets |
| Autumn Pineapple Lily | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 10-14 days during the growing season | Toxic to pets |
| autumn red grass | Direct sun (at least 4-6 hours) | Every 7–14 days during the growing season; reduce in autumn and winter | Pet-safe |
| Autumn Sage | Direct sun (at least 4-6 hours) | Occasional once established; regular for first season | Pet-safe |
| Autumn Squill | Direct sun (at least 4-6 hours) | Very sparingly; allow soil to dry completely between waterings, roughly every 14-21 days in active season | Toxic to pets |
| Avalanche Feather Reed Grass | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry, around weekly; tolerant of occasional wet ground | Pet-safe |
| Avalanche Reed Grass | Bright indirect light (just back from a sunny window) | Every 7-14 days; keep moderately moist in the growing season | Pet-safe |
| Azalea 'Firefly' | Bright indirect light (just back from a sunny window) | When the top 3 cm of soil is dry, roughly every 7-10 days during the growing season | Toxic to pets |
| Azalea 'Gibraltar' | Bright indirect light (just back from a sunny window) | Deeply once or twice a week in dry weather; keep consistently moist year-round | Toxic to pets |
| Azalea 'Hino-Crimson' | Bright indirect light (just back from a sunny window) | Deeply once a week; increase in hot, dry spells | Toxic to pets |
| Azalea 'Weston's Flamingo' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil feels dry, roughly every 5-7 days in summer; reduce in winter | Toxic to pets |
| Aztec Lily | Direct sun (at least 4-6 hours) | Regular watering while in active growth; keep dry during autumn–winter dormancy | Toxic to pets |
| Azure Grape Hyacinth | Direct sun (at least 4-6 hours) | Water during active growth; allow to dry out completely in summer | Mildly toxic to pets |
| Baboon Flower | Direct sun (at least 4-6 hours) | Regular during growth and flowering, dry during summer dormancy | Mildly toxic to pets |
| Baby Love Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season, more in heat or in pots | Pet-safe |
| Baby Sage | Direct sun (at least 4-6 hours) | Every 10–14 days once established | Pet-safe |
| Baby's breath | Direct sun (at least 4-6 hours) | Every 10–14 days when established; weekly when young | Mildly toxic to pets |
| Bachelor's button | Direct sun (at least 4-6 hours) | Every 7–10 days | Pet-safe |
| Bacopa | Bright indirect light (just back from a sunny window) | Every 2–3 days in containers during warm weather; reduce in cooler conditions | Pet-safe |
| Bacopa 'Scopia Gulliver Purple' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost starts to dry, often daily in warm weather | Pet-safe |
| Bacopa 'Snowtopia' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost begins to dry, often daily in warm weather | Pet-safe |
| Baker's Tulip | Direct sun (at least 4-6 hours) | Moderate in spring; dry in summer | Toxic to pets |
| Bald Cypress | Direct sun (at least 4-6 hours) | Daily in summer; can stand in a water tray during heat | Mildly toxic to pets |
| Bald Cypress Bonsai 'Cascade' | Direct sun (at least 4-6 hours) | Keep consistently moist; in summer often daily, and it can stand in a shallow water tray | Mildly toxic to pets |
| Balearic box | Bright indirect light (just back from a sunny window) | Weekly when young; every 10–14 days once established | Toxic to pets |
| Balkan Pink | Direct sun (at least 4-6 hours) | Low; water sparingly, allowing soil to dry fully between waterings | Mildly toxic to pets |
| Balkan Rock Pink | Direct sun (at least 4-6 hours) | Very infrequent; drought-tolerant | Mildly toxic to pets |
| Balkan Sage | Medium indirect light (a couple of metres from a window) | Weekly during dry spells | Pet-safe |
| Balkan Saxifrage | Direct sun (at least 4-6 hours) | Low — water at the base only; allow near-drying between waterings | Pet-safe |
| Ball Cactus | Direct sun (at least 4-6 hours) | When the top of the soil is dry, about every 7-10 days in summer; sparingly to none in winter | Pet-safe |
| Ballerina Rose | Direct sun (at least 4-6 hours) | Deep watering once or twice weekly | Pet-safe |
| Balsam Fir | Direct sun (at least 4-6 hours) | Weekly during establishment; naturally rainfall-sustained thereafter | Pet-safe |
| Bamboo Muhly | Direct sun (at least 4-6 hours) | Every 2–3 weeks in summer; monthly or less in winter once established | Pet-safe |
| Banana passionflower | Bright indirect light (just back from a sunny window) | Weekly in growing season, reduce in winter | Mildly toxic to pets |
| Banana passionfruit | Bright indirect light (just back from a sunny window) | Every 7–10 days; keep evenly moist | Mildly toxic to pets |
| Banded Cape Primrose | Bright indirect light (just back from a sunny window) | Every 5-7 days in the growing season; reduce to every 10-14 days in winter | Pet-safe |
| Baptisia 'Purple Smoke' | Direct sun (at least 4-6 hours) | Weekly the first season; minimal once established | Toxic to pets |
| Barrelier's Sage | Direct sun (at least 4-6 hours) | Weekly to establish, then fortnightly | Pet-safe |
| Barren Strawberry | Medium indirect light (a couple of metres from a window) | Low to moderate; drought-tolerant once established | Pet-safe |
| Basil-Leaved Sun Rose | Direct sun (at least 4-6 hours) | Very low — minimal supplemental irrigation needed once established | Mildly toxic to pets |
| Batalin's Tulip | Direct sun (at least 4-6 hours) | Light to moderate in spring; completely dry in summer | Toxic to pets |
| Beacon Silver Dead Nettle | Medium indirect light (a couple of metres from a window) | Every 7–10 days; water more frequently in sunny or dry situations | Pet-safe |
| Bear Tupelo | Bright indirect light (just back from a sunny window) | Regularly; keep consistently moist | Pet-safe |
| Bearberry Cotoneaster | Direct sun (at least 4-6 hours) | Fortnightly once established; more frequent for the first growing season | Mildly toxic to pets |
| Beardtongue 'Husker Red' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days during the growing season | Mildly toxic to pets |
| Beatrice Watsonia | Direct sun (at least 4-6 hours) | Regular throughout growing season; reduce but do not dry out in winter | Mildly toxic to pets |
| beautiful feather grass | Direct sun (at least 4-6 hours) | Weekly in the first season; minimal once established | Pet-safe |
| Beautiful Fuchsia | Bright indirect light (just back from a sunny window) | Water freely in growth; reduce in winter | Pet-safe |
| Beautiful Sea Holly | Direct sun (at least 4-6 hours) | Low — water sparingly once established | Mildly toxic to pets |
| Beavertail Cactus | Direct sun (at least 4-6 hours) | Very sparingly when soil is bone dry, roughly every 3-4 weeks in summer; keep dry in winter | Pet-safe |
| Becky Shasta daisy | Direct sun (at least 4-6 hours) | Every 5–7 days in the growing season; less in cool or wet weather | Mildly toxic to pets |
| Bedding Begonia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 3-5 days | Toxic to pets |
| Bee Balm 'Cambridge Scarlet' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Pet-safe |
| Bee Orchid | Bright indirect light (just back from a sunny window) | Low; drought-tolerant once established | Pet-safe |
| Begonia | Bright indirect light (just back from a sunny window) | Weekly watering | Toxic to pets |
| Begonia 'Barkos' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Begonia 'Bonfire' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, often daily in summer baskets | Toxic to pets |
| Begonia 'Corbeille de Feu' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 3-6 days in summer growth | Toxic to pets |
| Begonia 'Dragon Wing Pink' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Toxic to pets |
| Begonia 'Dragon Wing Red' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer containers | Toxic to pets |
| Begonia 'Escargot' Cocktail Series | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 5-7 days | Toxic to pets |
| Begonia 'Glowing Embers' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Toxic to pets |
| Begonia 'Illumination Orange' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, often daily in summer baskets | Toxic to pets |
| Begonia 'Illumination Salmon' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 3-6 days | Toxic to pets |
| Begonia 'Non-Stop Rose' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Toxic to pets |
| Begonia 'Nonstop Joy Salmon' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Toxic to pets |
| Begonia 'Nonstop Joy White' | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water when the surface begins to dry, often every 2-4 days in summer pots | Toxic to pets |
| Begonia 'Nonstop Red' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 2-4 days in summer | Toxic to pets |
| Begonia 'Nonstop Rose Petticoat' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 2-4 days in summer | Toxic to pets |
| Begonia 'Picotee Lace Pink' | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water when the surface begins to dry, often every 2-4 days in summer pots | Toxic to pets |
| Begonia 'Pin Up Flame' | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water when the surface begins to dry, often every 2-4 days in summer pots | Toxic to pets |
| Begonia 'Santa Cruz Sunset' | Bright indirect light (just back from a sunny window) | When top 2-3 cm of soil is dry, roughly every 3-5 days in summer | Toxic to pets |
| Begonia 'Senator White' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Begonia 'Varsity Red' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Begonia × semperflorens-cultorum 'Cocktail Vodka' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 3-5 days | Toxic to pets |
| Begonia × semperflorens-cultorum 'Dragon Wing Red' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 3-5 days in containers in summer | Toxic to pets |
| Begonia × tuberhybrida 'Non-Stop Mocca White' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 3-5 days in growth | Toxic to pets |
| Begonia × tuberhybrida 'Nonstop Rose' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is just dry, roughly every 2-4 days in summer | Toxic to pets |
| Begonia × tuberhybrida 'Pin-Up Flame' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is just dry, roughly every 2-4 days in summer | Toxic to pets |
| Begonia grandis | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly weekly in active growth | Toxic to pets |
| Begonia grandis subsp. evansiana | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist in summer; water during dry spells, roughly weekly in heat | Toxic to pets |
| Begonia schmidtiana | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days in growth | Toxic to pets |
| Begonia sutherlandii | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, every few days in summer | Toxic to pets |
| Bell heather | Direct sun (at least 4-6 hours) | Weekly when establishing; every 2–3 weeks once established | Pet-safe |
| Bell Heather C.D. Eason | Direct sun (at least 4-6 hours) | Moderate; water during dry spells, avoid waterlogging | Mildly toxic to pets |
| Belladonna larkspur | Direct sun (at least 4-6 hours) | Regular — deep water 2–3 times per week during growth; ease off in wet periods | Toxic to pets |
| Belladonna Lily | Direct sun (at least 4-6 hours) | Minimal or none in summer dormancy; regular from flower emergence through winter while foliage is active; reduce in late spring | Toxic to pets |
| Belle Etoile Mock Orange | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days | Mildly toxic to pets |
| Bellflower Codonopsis | Medium indirect light (a couple of metres from a window) | Water when the top 2–3 cm of soil is dry during the growing season; reduce significantly in winter | Mildly toxic to pets |
| Bellina Moth Orchid | Bright indirect light (just back from a sunny window) | Roughly every 5-7 days; when potting media is nearly dry but not bone dry | Pet-safe |
| Benary's Giant Coral zinnia | Direct sun (at least 4-6 hours) | Regular; water at soil level 2–3 times per week in dry weather | Pet-safe |
| Benary's Giant Coral Zinnia | Direct sun (at least 4-6 hours) | Water at the base every 5-7 days, allowing the top 3-5 cm of soil to dry between waterings; overhead watering should be avoided | Pet-safe |
| Beni-kaze Hakone Grass | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water 1-2 times weekly, more in heat | Mildly toxic to pets |
| Bent Enkianthus | Bright indirect light (just back from a sunny window) | Regular — keep consistently moist | Toxic to pets |
| Bent Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist through spring; tolerates slightly drier conditions during summer dormancy | Mildly toxic to pets |
| Beoley Gold heather | Direct sun (at least 4-6 hours) | Weekly during establishment; occasional watering once established in dry spells | Pet-safe |
| Berry Smoothie Heuchera | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Pet-safe |
| Besom heath | Direct sun (at least 4-6 hours) | Weekly during establishment; largely self-sufficient once established | Pet-safe |
| Betula nigra | Direct sun (at least 4-6 hours) | Keep consistently moist; tolerates wet soil | Mildly toxic to pets |
| Betula pendula | Direct sun (at least 4-6 hours) | Weekly while establishing; water in drought | Mildly toxic to pets |
| Betula pendula 'Youngii' | Direct sun (at least 4-6 hours) | Weekly while young; deep-water in dry spells | Mildly toxic to pets |
| Betula utilis var. jacquemontii | Direct sun (at least 4-6 hours) | Weekly while young; water deeply in dry summers | Mildly toxic to pets |
| Bicolor Barrenwort | Low light (north window or shaded room) | Regularly in the first season; once established, once every 2–3 weeks or rely on rainfall | Mildly toxic to pets |
| Bicolor St Dabeoc's heath | Direct sun (at least 4-6 hours) | Moderate; water regularly to keep soil moist, particularly in dry spells | Pet-safe |
| Bidens ferulifolia 'Bidy Gonzales' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in containers during summer heat | Pet-safe |
| Bidens ferulifolia 'Campfire Fireburst' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 2-4 days in summer containers | Pet-safe |
| Big Bluestem | Direct sun (at least 4-6 hours) | Every 2–3 weeks during establishment; rainfall-sufficient once established in most of its native range | Pet-safe |
| Big Kiss Yellow Flame Gazania | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days | Pet-safe |
| Big Red Sage | Bright indirect light (just back from a sunny window) | Moderate; keep evenly moist, especially during establishment | Pet-safe |
| Big-Flowered Catmint | Direct sun (at least 4-6 hours) | Every 7–10 days; allow soil surface to dry between waterings | Pet-safe |
| Bigcone Douglas Fir | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established | Pet-safe |
| Bigleaf Hydrangea 'Nikko Blue' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, often every 2-4 days in summer | Toxic to pets |
| Bigleaf Magnolia | Bright indirect light (just back from a sunny window) | Deeply twice weekly during establishment; weekly once established in dry periods | Pet-safe |
| Billy buttons | Direct sun (at least 4-6 hours) | Every 10–14 days; drought-tolerant once established | Mildly toxic to pets |
| Birchleaf Spirea | Direct sun (at least 4-6 hours) | Weekly until established; occasional watering in drought once mature | Pet-safe |
| Bird of paradise | Direct sun (at least 4-6 hours) | When the top 3 cm of soil is dry, every 7-10 days | Toxic to pets |
| Bird-in-a-bush | Medium indirect light (a couple of metres from a window) | Moderate in spring during active growth; dry during summer dormancy | Toxic to pets |
| Bird's Nest Spruce | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing; deep watering when the top 5 cm of soil is dry | Pet-safe |
| Bird's-nest Orchid | Low light (north window or shaded room) | Not applicable for cultivation; in nature, reliant on consistently moist woodland humus | Mildly toxic to pets |
| Bishop of Llandaff Dahlia | Direct sun (at least 4-6 hours) | 2–3 times per week in summer | Mildly toxic to pets |
| Bishop's flower | Direct sun (at least 4-6 hours) | Every 5–7 days; less once established | Mildly toxic to pets |
| Bitter Vetch | Medium indirect light (a couple of metres from a window) | Moderate — allow soil to approach dryness between waterings | Mildly toxic to pets |
| Bitterroot | Direct sun (at least 4-6 hours) | Winter rains / early spring only; bone dry from June to October | Pet-safe |
| Bitterroot Lewisia | Bright indirect light (just back from a sunny window) | Weekly in spring; monthly or less in summer dormancy | Pet-safe |
| Black Ash | Direct sun (at least 4-6 hours) | High; requires consistently moist to wet soil | Pet-safe |
| Black Ball cornflower | Direct sun (at least 4-6 hours) | Every 7–10 days | Pet-safe |
| Black Beauty Elderberry | Direct sun (at least 4-6 hours) | Weekly in the first two seasons; established plants tolerate short dry spells | Mildly toxic to pets |
| Black Calla Lily | Bright indirect light (just back from a sunny window) | Generously during active growth; taper off as foliage dies back; bone dry in dormancy | Toxic to pets |
| Black Cohosh | Medium indirect light (a couple of metres from a window) | 2–3 times per week in summer; weekly in cooler seasons | Mildly toxic to pets |
| Black Flowering Sedge | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist to wet; water whenever the surface begins to dry | Pet-safe |
| Black Knight Butterfly Bush | Direct sun (at least 4-6 hours) | Every 7-10 days during the first growing season; established plants are drought-tolerant and require supplemental watering only during extended dry spells | Toxic to pets |
| Black Knight scabiosa | Direct sun (at least 4-6 hours) | Once or twice weekly | Pet-safe |
| Black Lily Magnolia | Bright indirect light (just back from a sunny window) | Weekly during the growing season; reduce in winter | Pet-safe |
| Black Medick | Direct sun (at least 4-6 hours) | Low to moderate | Pet-safe |
| Black Mondo Grass | Medium indirect light (a couple of metres from a window) | Once a week during the growing season; reduce in winter | Mildly toxic to pets |
| Black Oak | Direct sun (at least 4-6 hours) | Rainfall-dependent once established; moderate supplemental irrigation in year 1–2 | Mildly toxic to pets |
| Black Pagoda Lipstick Plant | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Black Prince snapdragon | Direct sun (at least 4-6 hours) | Every 5–7 days; keep soil consistently moist | Pet-safe |
| Black Scallop Bugle | Medium indirect light (a couple of metres from a window) | Once or twice weekly; reduce to once weekly when established | Mildly toxic to pets |
| Black sedge | Bright indirect light (just back from a sunny window) | Keep constantly moist to wet; tolerates standing water | Pet-safe |
| Black Spruce | Direct sun (at least 4-6 hours) | Consistent moisture; tolerates waterlogging — does not dry out between waterings | Pet-safe |
| Black-Eyed Susan | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about weekly until established | Mildly toxic to pets |
| Black-eyed Susan 'Goldsturm' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry; moderately drought-tolerant once established after the first full season | Mildly toxic to pets |
| Black-eyed Susan vine | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-5 days in summer | Mildly toxic to pets |
| Black-Headed Fountain Grass | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2 weeks once established | Pet-safe |
| Black-Seeded Melic | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water in dry spells, especially in lighter shade | Mildly toxic to pets |
| Blackhaw Viburnum | Direct sun (at least 4-6 hours) | Weekly while establishing; established plants need water only in extended drought | Pet-safe |
| Bladder Campion | Bright indirect light (just back from a sunny window) | Low; drought-tolerant | Mildly toxic to pets |
| Bladder Cherry | Direct sun (at least 4-6 hours) | Weekly in the first season; established plants tolerate moderate drought | Toxic to pets |
| Blanc Double de Coubert Rose | Direct sun (at least 4-6 hours) | Weekly while establishing; drought-tolerant thereafter | Pet-safe |
| Blanket flower | Direct sun (at least 4-6 hours) | Every 7–14 days once established; water young plants more frequently | Pet-safe |
| Blanket Flower | Direct sun (at least 4-6 hours) | Water to establish, then sparingly; drought-tolerant | Mildly toxic to pets |
| Blanket Flower 'Goblin' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is fully dry, roughly every 10-14 days; minimal once established | Mildly toxic to pets |
| Blaze Improved Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season, more during heat | Pet-safe |
| Blechnum chilense | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 4-6 days | Mildly toxic to pets |
| Bleeding Heart | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry; roughly weekly, keeping soil consistently moist in spring | Toxic to pets |
| Bleeding Heart | Medium indirect light (a couple of metres from a window) | Every 5–7 days in spring; taper off as foliage yellows; minimal when dormant | Toxic to pets |
| Blonde Ambition Blue Grama | Direct sun (at least 4-6 hours) | Water through the first growing season, then only in severe drought, every 2-3 weeks at most | Mildly toxic to pets |
| Blood-Cupped Pink | Direct sun (at least 4-6 hours) | Infrequent; highly drought-tolerant once established | Mildly toxic to pets |
| Bloodgood Japanese Maple | Bright indirect light (just back from a sunny window) | When the top 3–5 cm of soil is dry, roughly every 5–7 days in summer; weekly to fortnightly in autumn and spring | Pet-safe |
| Bloodroot | Medium indirect light (a couple of metres from a window) | Every 5–7 days during spring growth; minimal or none during summer dormancy | Toxic to pets |
| Blue Anise Sage | Bright indirect light (just back from a sunny window) | Weekly | Pet-safe |
| Blue Arrow Juniper | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing, then deep occasional watering | Mildly toxic to pets |
| Blue Ash | Direct sun (at least 4-6 hours) | Regular in first 2 years; infrequent once established | Mildly toxic to pets |
| Blue Atlas Cedar | Direct sun (at least 4-6 hours) | Every 1-2 weeks while establishing, then rarely | Mildly toxic to pets |
| Blue Atlas Cedar | Direct sun (at least 4-6 hours) | Infrequently once established; moderate during first 2 years | Mildly toxic to pets |
| Blue Bells Bush Violet | Medium indirect light (a couple of metres from a window) | When the top 2 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Blue Bird Rose of Sharon | Direct sun (at least 4-6 hours) | Weekly during dry spells; reduce once established | Mildly toxic to pets |
| Blue blossom | Direct sun (at least 4-6 hours) | Weekly during establishment; minimal irrigation once established (drought-tolerant) | Mildly toxic to pets |
| Blue Boy cornflower | Direct sun (at least 4-6 hours) | Every 7–10 days | Pet-safe |
| Blue Carpet Juniper | Direct sun (at least 4-6 hours) | Every 7-10 days for the first season, then only in extended drought | Mildly toxic to pets |
| Blue China Fir | Direct sun (at least 4-6 hours) | Regular when young; moderate once established | Mildly toxic to pets |
| Blue China Fir | Direct sun (at least 4-6 hours) | Deeply once per week during the first two growing seasons; established plants are fairly drought-tolerant | Mildly toxic to pets |
| Blue Cloud Cranesbill | Bright indirect light (just back from a sunny window) | Moderate; water in dry spells | Mildly toxic to pets |
| Blue Cohosh | Low light (north window or shaded room) | Every 5–7 days; maintain consistently moist soil | Toxic to pets |
| Blue Columbine | Medium indirect light (a couple of metres from a window) | Water when the top 3 cm of soil dries, about weekly | Mildly toxic to pets |
| Blue Creeping Speedwell | Direct sun (at least 4-6 hours) | Moderate; allow the top few centimetres to dry between waterings | Pet-safe |
| Blue Douglas Fir | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-14 days when young | Mildly toxic to pets |
| Blue Fescue | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; sparingly once established | Mildly toxic to pets |
| Blue Giant Sequoia | Direct sun (at least 4-6 hours) | Deeply weekly for 3–5 years during establishment | Pet-safe |
| Blue Grama Grass | Direct sun (at least 4-6 hours) | Water to establish in the first season; thereafter only in extreme drought, roughly every 2-3 weeks if at all | Mildly toxic to pets |
| Blue Hair Grass | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; water sparingly | Pet-safe |
| Blue Heaven Little Bluestem | Direct sun (at least 4-6 hours) | Every 14-21 days once established; very drought-tolerant | Pet-safe |
| Blue Holly 'Blue Princess' | Bright indirect light (just back from a sunny window) | Weekly while establishing, then during dry spells | Toxic to pets |
| Blue Ice Arizona Cypress | Direct sun (at least 4-6 hours) | Every 10-14 days while establishing; drought-tolerant once established | Mildly toxic to pets |
| Blue Ice bog rosemary | Bright indirect light (just back from a sunny window) | Consistently moist; never allow to dry out | Toxic to pets |
| Blue Lyme Grass | Direct sun (at least 4-6 hours) | Drought-tolerant; water only in prolonged dry spells once established | Mildly toxic to pets |
| Blue Mistflower | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water weekly, more in heat or sandy soil | Mildly toxic to pets |
| Blue Moor Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; rarely thereafter except in extended drought | Mildly toxic to pets |
| Blue Mouse Ears Hosta | Low light (north window or shaded room) | Keep soil consistently moist, watering when the top 2-3 cm begins to dry, often weekly or more in summer | Toxic to pets |
| Blue Oat Grass | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Pet-safe |
| Blue Oat Grass | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing, then occasionally | Mildly toxic to pets |
| Blue Passion Flower | Direct sun (at least 4-6 hours) | Water thoroughly when the top 3-5 cm of soil is dry, roughly every 7-10 days; more frequently in hot summers, reduce significantly in winter | Toxic to pets |
| Blue Pickerelweed | Direct sun (at least 4-6 hours) | Rooted marginal — grow in wet soil or water up to 15 cm (6 in) deep | Pet-safe |
| Blue Potato Bush | Direct sun (at least 4-6 hours) | Every 4-6 days in summer, every 10-14 days in cooler months | Toxic to pets |
| Blue Prince Holly | Direct sun (at least 4-6 hours) | Weekly deep watering while establishing, then every 7-10 days in dry spells | Toxic to pets |
| Blue Princess Holly | Direct sun (at least 4-6 hours) | Weekly deep watering while establishing, then every 7-10 days in dry spells | Toxic to pets |
| Blue Ridge Creeping Phlox | Medium indirect light (a couple of metres from a window) | Weekly in the first season; every 1–2 weeks once established | Pet-safe |
| Blue sedge | Bright indirect light (just back from a sunny window) | Water regularly until established; minimal thereafter | Pet-safe |
| Blue Spurflower | Medium indirect light (a couple of metres from a window) | Moderate — water once or twice weekly in summer; reduce significantly in winter | Mildly toxic to pets |
| Blue Star Juniper | Direct sun (at least 4-6 hours) | Water through the first season; afterward only in prolonged dry spells | Toxic to pets |
| Blue Star Water Lily | Direct sun (at least 4-6 hours) | Continuously aquatic — grow in still or slow-moving water 6–18 in (15–45 cm) deep. | Mildly toxic to pets |
| Blue Surprise Cypress | Direct sun (at least 4-6 hours) | Keep evenly moist; deep weekly watering while establishing, then in dry periods | Toxic to pets |
| Blue Tulp | Direct sun (at least 4-6 hours) | Water sparingly in autumn and winter when growing; completely dry in summer | Toxic to pets |
| Blue Vanda | Direct sun (at least 4-6 hours) | Daily in warm months when roots silver over; every 2-3 days in cool, dim weather | Pet-safe |
| Blue Wild Indigo | Direct sun (at least 4-6 hours) | Water the first year; established plants rarely need watering | Mildly toxic to pets |
| Blue Wild Rye | Direct sun (at least 4-6 hours) | Water moderately when the top few cm of soil dry; avoid soggy conditions | Mildly toxic to pets |
| Blue Zinger Sedge | Direct sun (at least 4-6 hours) | Water to establish, then drought-tolerant; occasional watering in long dry spells | Mildly toxic to pets |
| Bluebird Mountain Hydrangea | Bright indirect light (just back from a sunny window) | Deeply once or twice a week during the growing season; reduce in autumn and winter | Mildly toxic to pets |
| bluejoint reedgrass | Direct sun (at least 4-6 hours) | Keep consistently moist to wet; suited to boggy and seasonally flooded ground | Pet-safe |
| Bluish Sage | Direct sun (at least 4-6 hours) | Low — water when soil is dry 5–7 cm deep | Mildly toxic to pets |
| Blushing Arisaema | Medium indirect light (a couple of metres from a window) | Regularly during growing season; minimal in dormancy | Toxic to pets |
| Boat Orchid | Bright indirect light (just back from a sunny window) | Spring-summer: keep evenly moist, roughly weekly; autumn-winter: reduce to weekly or fortnightly when barely damp | Mildly toxic to pets |
| Boat Orchid | Direct sun (at least 4-6 hours) | When the mix is dry, roughly every 7-10 days, less in winter | Pet-safe |
| Bodinier's beautyberry | Direct sun (at least 4-6 hours) | Weekly during the first two growing seasons; every 2–3 weeks once established | Mildly toxic to pets |
| Bog Arum | Medium indirect light (a couple of metres from a window) | Saturated soil or up to 15 cm of standing water | Toxic to pets |
| Bog Laurel | Bright indirect light (just back from a sunny window) | Frequent; keep soil consistently moist to wet | Toxic to pets |
| Bog rosemary | Bright indirect light (just back from a sunny window) | Consistently moist; never allow to dry out | Toxic to pets |
| Bog Sage | Direct sun (at least 4-6 hours) | Moderate to high — keep soil consistently moist | Mildly toxic to pets |
| Boissier's Silverbush | Direct sun (at least 4-6 hours) | Very infrequent once established | Mildly toxic to pets |
| Bokhara Iris | Direct sun (at least 4-6 hours) | Moderate in spring; completely dry from midsummer to autumn | Toxic to pets |
| Bolero Painted Tongue | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Boliviensis Begonia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, often daily in summer baskets | Toxic to pets |
| Bon Bon Mix Pot Marigold | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Bonica Rose | Direct sun (at least 4-6 hours) | Deep watering once or twice weekly | Pet-safe |
| Border Forsythia | Direct sun (at least 4-6 hours) | Weekly during the first year, then only in prolonged drought | Pet-safe |
| Boscobel Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season; more in heat or sandy soil | Pet-safe |
| Bosnian Pine | Direct sun (at least 4-6 hours) | Water young trees weekly in dry spells; established trees rarely need it | Mildly toxic to pets |
| Bosnian Pine 'Compact Gem' | Direct sun (at least 4-6 hours) | Water weekly in dry spells while establishing; little needed thereafter | Mildly toxic to pets |
| Bottle Gentian | Medium indirect light (a couple of metres from a window) | Regular — keep soil consistently moist | Pet-safe |
| Bougainvillea | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry out | Mildly toxic to pets |
| Bougainvillea 'Barbara Karst' | Direct sun (at least 4-6 hours) | Deeply but infrequently, only when the top 5 cm of soil is dry, roughly every 7-14 days | Pet-safe |
| Bougainvillea 'Raspberry Ice' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 5-10 days | Pet-safe |
| Bougainvillea 'San Diego Red' | Direct sun (at least 4-6 hours) | Deep soak only when the top 5 cm of soil dries, about every 7-14 days | Pet-safe |
| Boulder Blue Fescue | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; sparingly once established | Mildly toxic to pets |
| Boulevard Cypress | Direct sun (at least 4-6 hours) | Every 4-7 days while establishing, then when the top few cm of soil dry | Mildly toxic to pets |
| Bove's Jerusalem Sage | Direct sun (at least 4-6 hours) | Low — once every 2–3 weeks during active growth; essentially none from late autumn to early spring | Mildly toxic to pets |
| Bowden Lily | Direct sun (at least 4-6 hours) | Minimal in summer; moderate from flowering through winter and spring while foliage is present; none once foliage dies back | Toxic to pets |
| Bowl Lotus | Direct sun (at least 4-6 hours) | Keep submerged at all times; never allow the rhizome to dry out | Pet-safe |
| Bowles Golden Sedge | Direct sun (at least 4-6 hours) | Keep wet to constantly moist; never allow to dry out | Mildly toxic to pets |
| box honeysuckle | Bright indirect light (just back from a sunny window) | Regularly during the first season; drought-tolerant once established | Mildly toxic to pets |
| Bracken's Brown Beauty Magnolia | Direct sun (at least 4-6 hours) | Deeply weekly during the first 2–3 years; every 2–3 weeks once established | Mildly toxic to pets |
| Bracted Spiderwort | Bright indirect light (just back from a sunny window) | Fortnightly or less once established | Mildly toxic to pets |
| Bradbury's Beardtongue | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; rarely in winter | Mildly toxic to pets |
| Brandy Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season | Pet-safe |
| Brassia 'Rex' | Bright indirect light (just back from a sunny window) | When the bark surface dries, about every 5-7 days in growth | Mildly toxic to pets |
| Brassia caudata | Bright indirect light (just back from a sunny window) | Water thoroughly, then let the top of the mix approach dryness; about every 5-7 days in growth | Pet-safe |
| Brazilian Edelweiss | Bright indirect light (just back from a sunny window) | When the top few cm of soil are dry during active growth; withhold during dormancy | Pet-safe |
| Brazilian Jasmine | Direct sun (at least 4-6 hours) | Let the top 2-3 cm of soil dry, then water; roughly every 4-7 days, more often in heat | Mildly toxic to pets |
| Bressingham White Bergenia | Medium indirect light (a couple of metres from a window) | Every 7–10 days during the growing season; reduce in autumn and winter | Pet-safe |
| Brewer Spruce | Direct sun (at least 4-6 hours) | Moderate — water regularly during establishment; tolerates summer drought once established | Pet-safe |
| Brewer's Mountain Heather | Bright indirect light (just back from a sunny window) | Regular; keep soil consistently moist | Mildly toxic to pets |
| Bridal Wreath Spirea | Direct sun (at least 4-6 hours) | Water when the top 5 cm of soil is dry, about weekly while establishing | Pet-safe |
| Bridal Wreath Spirea | Direct sun (at least 4-6 hours) | Every 7-10 days during dry spells; established plants are drought-tolerant | Pet-safe |
| Bright Bikinis strawflower | Direct sun (at least 4-6 hours) | Every 5–7 days; allow soil to dry slightly between waterings | Mildly toxic to pets |
| Bright Bikinis Strawflower | Direct sun (at least 4-6 hours) | When the top 3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Brilliantissima red chokeberry | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once established | Pet-safe |
| Bristlecone Pine | Direct sun (at least 4-6 hours) | Infrequent deep watering, roughly every 2-3 weeks; allow thorough drying | Mildly toxic to pets |
| Bristol Ruby Weigela | Direct sun (at least 4-6 hours) | Every 7-10 days during dry spells; established plants cope with moderate drought | Pet-safe |
| British Yellowhead | Direct sun (at least 4-6 hours) | Once or twice per week; drought-tolerant once established | Pet-safe |
| Britt-Marie Crawford Ligularia | Medium indirect light (a couple of metres from a window) | Constantly moist to wet; never allow to dry out — water generously in any dry spell, sometimes daily in heat | Mildly toxic to pets |
| Broad-leaved Grape Hyacinth | Direct sun (at least 4-6 hours) | Once per week during active spring growth; allow to dry out during summer dormancy | Toxic to pets |
| Broad-Leaved Grape Hyacinth | Bright indirect light (just back from a sunny window) | Low once established; moderate during active growth | Toxic to pets |
| Broad-leaved Helleborine | Medium indirect light (a couple of metres from a window) | Regular during dry spells; keep consistently moist but not waterlogged | Mildly toxic to pets |
| Broad-Leaved Lime | Bright indirect light (just back from a sunny window) | Weekly during establishment; supplemental watering in prolonged drought | Pet-safe |
| Broad-leaved Pondweed | Direct sun (at least 4-6 hours) | Fully submerged aquatic; grows in 30 cm to 150 cm of water | Pet-safe |
| Broad-Leaved Primrose | Medium indirect light (a couple of metres from a window) | Regularly throughout the growing season; reduced in winter | Toxic to pets |
| Broad-Leaved Sea Lavender | Direct sun (at least 4-6 hours) | Every 2–3 weeks when established | Pet-safe |
| Broad-Petalled Cranesbill | Bright indirect light (just back from a sunny window) | Once or twice a week in the growing season; less in winter | Pet-safe |
| Bromeliad | Bright indirect light (just back from a sunny window) | Keep the central cup filled, soil barely moist | Pet-safe |
| Bronze Sedge | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Mildly toxic to pets |
| Broomsedge Bluestem | Direct sun (at least 4-6 hours) | Rainfall sufficient; no supplemental irrigation needed once established | Pet-safe |
| Brown-eyed Susan | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; roughly weekly, more during drought | Mildly toxic to pets |
| Brunnera macrophylla | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7 days | Mildly toxic to pets |
| Brunnera macrophylla 'Jack Frost' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Brunnera macrophylla 'Looking Glass' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Buchanan's Sage | Bright indirect light (just back from a sunny window) | Every 5-7 days during the growing season | Pet-safe |
| Buckley's Beardtongue | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; very little in winter | Mildly toxic to pets |
| Buddleja 'Lo and Behold Blue Chip' | Direct sun (at least 4-6 hours) | Weekly while establishing, then only in dry spells | Mildly toxic to pets |
| Buddleja 'Miss Ruby' | Direct sun (at least 4-6 hours) | Weekly during establishment, then only in drought | Mildly toxic to pets |
| Buddleja alternifolia | Direct sun (at least 4-6 hours) | Weekly while establishing, then only in drought | Mildly toxic to pets |
| Buddleja davidii 'White Profusion' | Direct sun (at least 4-6 hours) | Weekly while establishing, then only in dry spells | Mildly toxic to pets |
| Buddleja globosa | Direct sun (at least 4-6 hours) | Weekly while establishing; occasional deep watering in summer droughts once mature | Mildly toxic to pets |
| Buff Beauty Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season; more in heat or against a warm wall | Pet-safe |
| Bugle | Medium indirect light (a couple of metres from a window) | Moderate; keep evenly moist but never waterlogged | Pet-safe |
| Bugle Lily | Direct sun (at least 4-6 hours) | Regular during growth; reduce in winter | Mildly toxic to pets |
| Bulb Sparaxis | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 10-14 days in spring | Mildly toxic to pets |
| Bulbil Bugle Lily | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-14 days during active growth | Mildly toxic to pets |
| Bulbophyllum falcatum | Bright indirect light (just back from a sunny window) | Water when the roots and medium approach dryness, roughly every 2-4 days when mounted, less in pots | Pet-safe |
| Bulbophyllum longissimum | Bright indirect light (just back from a sunny window) | Water as the medium nears dryness, roughly every 2-4 days; more often when mounted in warm weather | Pet-safe |
| Bulbophyllum vaginatum | Bright indirect light (just back from a sunny window) | Water as the medium approaches dryness, around every 2-4 days; daily when mounted in heat | Pet-safe |
| Bulbous Buttercup | Direct sun (at least 4-6 hours) | Once weekly or less; drought-tolerant once established | Toxic to pets |
| Bulbous Corydalis | Medium indirect light (a couple of metres from a window) | Rely on natural rainfall during spring growth; no irrigation needed once dormant in summer | Toxic to pets |
| Bunch-flowered Narcissus | Bright indirect light (just back from a sunny window) | Moderate and consistent during active growth; reduce sharply as foliage yellows; dormant dry | Toxic to pets |
| Burgundy Glow Bugle | Medium indirect light (a couple of metres from a window) | Moderate; consistently moist but not waterlogged | Mildly toxic to pets |
| Burgundy Periwinkle | Medium indirect light (a couple of metres from a window) | Weekly during establishment; every 2–3 weeks once established | Toxic to pets |
| Burkwood Viburnum | Direct sun (at least 4-6 hours) | Water when the top 5 cm of soil dries, roughly weekly during establishment | Pet-safe |
| Burnet Rose | Direct sun (at least 4-6 hours) | Weekly during establishment; rarely once mature | Pet-safe |
| Burser's Saxifrage | Bright indirect light (just back from a sunny window) | Every 7–10 days during growth; minimal in winter | Pet-safe |
| Bush Muhly | Direct sun (at least 4-6 hours) | Every 14-21 days during establishment; essentially rainfall-dependent once established in suitable climates | Pet-safe |
| Bush Vetch | Bright indirect light (just back from a sunny window) | Low to moderate — maintain moderate soil moisture | Mildly toxic to pets |
| Bushgrass | Medium indirect light (a couple of metres from a window) | Moderate — water regularly to establish, then largely drought-tolerant | Pet-safe |
| Bushy Bluestem | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Butomus umbellatus | Direct sun (at least 4-6 hours) | Constantly wet; shallow margin | Mildly toxic to pets |
| Butterfly bush | Direct sun (at least 4-6 hours) | Every 1–2 weeks during establishment; drought-tolerant once established | Mildly toxic to pets |
| Butterfly Bush 'Black Knight' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry; weekly in the first season, then only in prolonged drought | Mildly toxic to pets |
| Butterfly Bush 'Pink Delight' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry; weekly through the first year, then sparingly | Mildly toxic to pets |
| Butterfly Gladiolus | Direct sun (at least 4-6 hours) | Regular during active growth (summer–autumn); reduce as foliage dies; dry rest in winter | Toxic to pets |
| Butterfly Weed | Direct sun (at least 4-6 hours) | Water to establish, then only during prolonged drought; mature plants rarely need watering | Toxic to pets |
| Buttonhole Orchid | Direct sun (at least 4-6 hours) | When the top of the mix dries, roughly every 5-9 days | Pet-safe |
| Byzantine Colchicum | Bright indirect light (just back from a sunny window) | Relies on natural rainfall; do not water during summer dormancy | Toxic to pets |
| Byzantine Gladiolus | Direct sun (at least 4-6 hours) | Moderate during spring growth; minimal in summer after dormancy | Toxic to pets |
| Byzantine Meadow Saffron | Bright indirect light (just back from a sunny window) | Relies on natural rainfall; needs no supplementary watering once established | Toxic to pets |
| C.D. Eason bell heather | Direct sun (at least 4-6 hours) | Weekly while establishing; every 2–3 weeks once settled | Pet-safe |
| Cadiz Thrift | Direct sun (at least 4-6 hours) | Every 2–3 weeks during the growing season; very rarely in winter | Mildly toxic to pets |
| Café au Lait Dahlia | Direct sun (at least 4-6 hours) | 2–3 times per week | Mildly toxic to pets |
| Calathea Loeseneri (Brazilian Star) | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil dries, roughly every 5-7 days in growth | Pet-safe |
| Calceolaria Herbeohybrida | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost feels dry, roughly every 2-4 days while in flower | Mildly toxic to pets |
| Calendula | Direct sun (at least 4-6 hours) | Moderate — roughly weekly once established | Pet-safe |
| Calendula 'Indian Prince' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of soil is dry, roughly weekly | Pet-safe |
| Calendula 'Radio' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of soil is dry, roughly weekly | Pet-safe |
| Calibrachoa 'Cabaret Deep Blue' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, often daily in summer baskets | Pet-safe |
| Calibrachoa 'MiniFamous Double Amethyst' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, often daily in hot weather | Pet-safe |
| Calibrachoa 'Superbells Lemon Slice' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, often daily in baskets during summer heat | Pet-safe |
| Calibrachoa 'Superbells Trailing Blue' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, frequently daily in summer baskets | Pet-safe |
| Calico Aster | Bright indirect light (just back from a sunny window) | Water to establish, then occasionally; tolerates dry soil | Pet-safe |
| California Barrel Cactus | Direct sun (at least 4-6 hours) | Every 2-4 weeks in active growth; none in winter | Mildly toxic to pets |
| California Fawn Lily | Medium indirect light (a couple of metres from a window) | Regular in spring growing season; minimal during summer dormancy | Mildly toxic to pets |
| California Fescue | Bright indirect light (just back from a sunny window) | Water every 10-14 days during the first growing season; established plants are summer-dormant and very drought-tolerant, needing little or no supplemental water | Pet-safe |
| California Juniper | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, often every 3-5 days in heat | Mildly toxic to pets |
| California Nutmeg | Medium indirect light (a couple of metres from a window) | Every 7–10 days; do not allow to dry out fully, especially when young | Mildly toxic to pets |
| California poppy | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; more frequent during germination | Mildly toxic to pets |
| Calla Lily | Bright indirect light (just back from a sunny window) | Keep consistently moist during active growth; reduce sharply for winter dormancy | Toxic to pets |
| Callicarpa 'Pearl Glam' | Direct sun (at least 4-6 hours) | Water weekly during the first season; established plants are fairly drought-tolerant and need water mainly in dry spells | Pet-safe |
| Callicarpa americana | Bright indirect light (just back from a sunny window) | Water weekly while establishing; once established, only during prolonged drought | Mildly toxic to pets |
| Callicarpa bodinieri var. giraldii 'Profusion' | Bright indirect light (just back from a sunny window) | Water weekly during establishment and in dry spells; established plants are moderately drought-tolerant | Mildly toxic to pets |
| Callicarpa dichotoma | Bright indirect light (just back from a sunny window) | Water weekly during establishment and dry periods; moderately drought-tolerant once established | Mildly toxic to pets |
| Callicarpa japonica | Bright indirect light (just back from a sunny window) | Water weekly while establishing and during droughts; moderately drought-tolerant once settled | Mildly toxic to pets |
| Callus Slipper Orchid | Medium indirect light (a couple of metres from a window) | When the top of the mix begins to dry, roughly every 5-7 days | Pet-safe |
| Caltha palustris | Direct sun (at least 4-6 hours) | Keep wet at all times; saturated soil or shallow water | Toxic to pets |
| Caltha palustris 'Flore Pleno' | Direct sun (at least 4-6 hours) | Keep wet at all times; saturated soil or shallow water | Toxic to pets |
| Camas | Bright indirect light (just back from a sunny window) | Regular during spring growth; tolerates summer drought when dormant | Pet-safe |
| Camassia leichtlinii | Direct sun (at least 4-6 hours) | Keep soil consistently moist in spring during active growth; tolerates dry dormancy in summer | Mildly toxic to pets |
| Cambria Orchid | Bright indirect light (just back from a sunny window) | When the surface of the mix begins to dry, roughly every 4-7 days | Pet-safe |
| Camellia 'Alba Plena' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, every 7-10 days during active growth | Pet-safe |
| Camellia 'Anticipation' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 7-10 days during the growing season | Pet-safe |
| Camellia 'Bob Hope' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days during the growing season | Pet-safe |
| Camellia 'Brushfield's Yellow' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost or soil is dry, roughly every 5-7 days during active growth | Pet-safe |
| Camellia 'Debbie' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Camellia 'Dixie Knight' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil or compost is dry, roughly every 5-7 days in the growing season | Pet-safe |
| Camellia 'Donation' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry; keep evenly moist in late summer | Pet-safe |
| Camellia 'Elegans' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days during growth | Pet-safe |
| Camellia 'Hagoromo' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost or soil is dry, roughly every 5-7 days during active growth | Pet-safe |
| Camellia 'J.C. Williams' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 7-10 days during the growing season | Pet-safe |
| Camellia 'Jury's Yellow' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water deeply once or twice weekly in summer, especially during bud set | Pet-safe |
| Camellia 'Jury's Yellow' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 7-10 days during active growth | Pet-safe |
| Camellia 'Kramer's Supreme' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days during active growth | Pet-safe |
| Camellia 'Midnight Magic' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 7-10 days during active growth | Pet-safe |
| Camellia 'Mine-no-Yuki' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 7-10 days through the growing season | Pet-safe |
| Camellia 'Nuccio's Gem' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 7-10 days in active growth | Pet-safe |
| Camellia 'Spring Festival' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Pet-safe |
| Camellia 'Water Lily' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil or compost is dry, roughly every 5-7 days during the growing season | Pet-safe |
| Camellia 'Yuletide' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days during active growth | Pet-safe |
| Campanula glomerata 'Superba' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries, about weekly in dry spells | Pet-safe |
| Campanula lactiflora 'Loddon Anna' | Direct sun (at least 4-6 hours) | Keep evenly moist; water deeply in dry spells, roughly weekly once established | Mildly toxic to pets |
| Campanula persicifolia | Direct sun (at least 4-6 hours) | Water during establishment and dry spells; roughly weekly in summer drought once settled | Mildly toxic to pets |
| Campanula portenschlagiana | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly weekly in summer | Mildly toxic to pets |
| Campanula poscharskyana | Bright indirect light (just back from a sunny window) | When the top few centimetres of soil dry out, weekly in hot spells | Mildly toxic to pets |
| Campanula punctata | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry; keep consistently moist in summer | Mildly toxic to pets |
| Campbell's Magnolia | Direct sun (at least 4-6 hours) | Every 7-10 days during the first three growing seasons; established trees need watering only during prolonged summer drought | Pet-safe |
| Campos Porto Fuchsia | Bright indirect light (just back from a sunny window) | Regular during growth; reduce in winter | Pet-safe |
| Campsis grandiflora | Direct sun (at least 4-6 hours) | When the top 5 cm of soil dries, about every 7-10 days while establishing | Mildly toxic to pets |
| Campsis radicans | Direct sun (at least 4-6 hours) | When the top 5 cm of soil dries, about every 7-14 days for young plants | Mildly toxic to pets |
| Campsis x tagliabuana 'Madame Galen' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil dries, about every 7-14 days while establishing | Mildly toxic to pets |
| Can Can Heuchera | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the top 2-3 cm is dry, about every 5-7 days in summer | Pet-safe |
| Canada Mayflower | Low light (north window or shaded room) | 2–3 times per week during the growing season; minimal in dormancy | Mildly toxic to pets |
| Canada Violet | Medium indirect light (a couple of metres from a window) | Weekly; more frequently in warm or dry periods | Mildly toxic to pets |
| Canadian Lousewort | Medium indirect light (a couple of metres from a window) | Regularly; keep soil evenly moist | Mildly toxic to pets |
| Canadian Wild Ginger | Low light (north window or shaded room) | Water weekly, or when the top 2–3 cm of soil feels dry | Mildly toxic to pets |
| Canadian Yew | Low light (north window or shaded room) | Weekly during establishment; every 1–2 weeks once established | Toxic to pets |
| Canary creeper | Bright indirect light (just back from a sunny window) | Water regularly to keep soil evenly moist, roughly every 5–7 days | Pet-safe |
| Canary Island Sage | Direct sun (at least 4-6 hours) | Every 10-14 days; minimal in cool or wet periods | Pet-safe |
| Canary Island Sea Lavender | Direct sun (at least 4-6 hours) | Every 1–2 weeks in growth; monthly in winter | Pet-safe |
| Canary Reed Grass | Bright indirect light (just back from a sunny window) | Keep consistently moist to wet; tolerates standing water | Mildly toxic to pets |
| Candelabra Lily | Direct sun (at least 4-6 hours) | Water moderately from first autumn rains (flower emergence) through winter-spring leaf period; keep bone dry all summer | Toxic to pets |
| Candelabra Sage | Direct sun (at least 4-6 hours) | Every 10-14 days in the growing season | Pet-safe |
| Candle larkspur | Direct sun (at least 4-6 hours) | Regular — deep watering 2–3 times per week during active growth; reduce in dormancy | Toxic to pets |
| Candle Larkspur 'Guardian Blue' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Candy Cane Sorrel | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 7-10 days during active growth | Mildly toxic to pets |
| Candy Stripe Creeping Phlox | Direct sun (at least 4-6 hours) | Every 7–10 days during the establishment year; drought-tolerant thereafter | Pet-safe |
| Canna 'Bengal Tiger' | Direct sun (at least 4-6 hours) | Water every 2-3 days in summer to keep soil consistently moist | Mildly toxic to pets |
| Canna 'Black Knight' | Direct sun (at least 4-6 hours) | Keep evenly moist throughout the growing season, watering every 2-4 days depending on temperature | Mildly toxic to pets |
| Canna 'Cleopatra' | Direct sun (at least 4-6 hours) | Water regularly to maintain consistently moist soil, approximately every 2-3 days in warm weather | Mildly toxic to pets |
| Canna 'Durban' | Direct sun (at least 4-6 hours) | Water regularly to keep soil evenly moist, roughly every 2-3 days in summer heat | Mildly toxic to pets |
| Canna 'Pacific Beauty' | Direct sun (at least 4-6 hours) | Water every 2-3 days to keep the soil consistently moist during the growing season | Mildly toxic to pets |
| Canna 'Phasion' | Direct sun (at least 4-6 hours) | Keep consistently moist; water every 2-3 days in warm weather, more often in containers | Mildly toxic to pets |
| Canna 'Pink Sunburst' | Direct sun (at least 4-6 hours) | Keep evenly moist throughout the growing season, watering every 2-3 days or whenever the top few centimetres become dry | Mildly toxic to pets |
| Canna 'Pretoria' | Direct sun (at least 4-6 hours) | Water deeply 2-3 times per week during the growing season; reduce sharply once foliage dies back in autumn | Mildly toxic to pets |
| Canna 'Red King Humbert' | Direct sun (at least 4-6 hours) | Water deeply 2-3 times per week in summer; reduce once foliage begins to die back in autumn | Mildly toxic to pets |
| Canna 'Roi Humbert' | Direct sun (at least 4-6 hours) | Keep soil consistently moist, watering every 2-3 days in warm weather or whenever the top 2-3 cm dries out | Mildly toxic to pets |
| Canna 'Striped Beauty' | Direct sun (at least 4-6 hours) | Water every 2-4 days to maintain moist (not soggy) soil throughout the growing season | Mildly toxic to pets |
| Canna 'The President' | Direct sun (at least 4-6 hours) | Water every 2-3 days in summer to maintain evenly moist soil | Mildly toxic to pets |
| Canna 'Tropicanna' | Direct sun (at least 4-6 hours) | Water deeply 2-3 times per week during summer; reduce watering once plants go dormant in autumn | Mildly toxic to pets |
| Canna 'Wyoming' | Direct sun (at least 4-6 hours) | Water deeply 2-3 times per week during summer; taper off in autumn as growth slows | Mildly toxic to pets |
| Canna 'Yellow King Humbert' | Direct sun (at least 4-6 hours) | Water every 2-3 days to maintain consistently moist soil during the growing season | Mildly toxic to pets |
| Cantabrian Draba | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Mildly toxic to pets |
| Canyon Sage | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established | Pet-safe |
| Cape Bugle Lily | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during active growth | Mildly toxic to pets |
| Cape daisy | Direct sun (at least 4-6 hours) | Every 4–6 days once established; more frequently in containers during warm weather | Mildly toxic to pets |
| Cape Gold Everlasting | Direct sun (at least 4-6 hours) | Every 2–3 weeks in summer; once a month or less in winter | Mildly toxic to pets |
| Cape jewels | Direct sun (at least 4-6 hours) | Every 3–5 days in containers; every 5–7 days in borders | Pet-safe |
| Cape Leadwort (Blue Plumbago) | Direct sun (at least 4-6 hours) | Weekly in active growth; let the top of the soil dry between waterings | Mildly toxic to pets |
| Cape Mallow | Direct sun (at least 4-6 hours) | Water when the top 2–3 cm of soil is dry | Mildly toxic to pets |
| Cape Primrose | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry; less in winter | Pet-safe |
| Cape Primrose | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 7-10 days | Pet-safe |
| Cape Primrose 'Bristol's Party Girl' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Caradonna Salvia | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about weekly until established | Pet-safe |
| Cardinal climber | Direct sun (at least 4-6 hours) | Once or twice a week; approximately 2.5 cm (1 in) per week | Toxic to pets |
| Cardinal Flower Sinningia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Pet-safe |
| Cardinal Royal rowan | Direct sun (at least 4-6 hours) | Regular during the first season; drought-tolerant once established | Mildly toxic to pets |
| Carding Mill Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week through the growing season, more in heat | Pet-safe |
| Carefree Wonder Rose | Direct sun (at least 4-6 hours) | Deep soak once or twice a week depending on heat | Pet-safe |
| Carex pendula | Medium indirect light (a couple of metres from a window) | Keep soil moist; water in dry spells | Mildly toxic to pets |
| Carex riparia 'Variegata' | Direct sun (at least 4-6 hours) | Keep wet to shallowly submerged at all times | Mildly toxic to pets |
| Carmine Begonia | Bright indirect light (just back from a sunny window) | When the top 1 inch of soil is dry | Toxic to pets |
| Carolina Hemlock | Bright indirect light (just back from a sunny window) | Weekly during establishment; monthly deep watering once established in cool climates | Pet-safe |
| Carolina Queen Lotus | Direct sun (at least 4-6 hours) | Permanently submerged; maintain 5–15 cm (2–6 in) of water over the soil surface for established plants | Pet-safe |
| Carolina Spring Beauty | Medium indirect light (a couple of metres from a window) | Moderate during active spring growth; essentially none during summer–winter dormancy. | Pet-safe |
| Carousel Little Bluestem | Direct sun (at least 4-6 hours) | Every 14-21 days during establishment; minimal once established | Pet-safe |
| Carpathian bellflower | Direct sun (at least 4-6 hours) | Every 5–7 days during active growth; moderate moisture needs | Pet-safe |
| Carrion Flower (Stapelia gigantea) | Direct sun (at least 4-6 hours) | Every 2-3 weeks in active growth (spring-autumn); keep nearly dry in winter | Pet-safe |
| Carrot-leaved Pelargonium | Direct sun (at least 4-6 hours) | Water when the top 2–3 cm of compost is dry during growth (autumn–spring); completely dry in summer dormancy | Toxic to pets |
| Caryopteris incana | Direct sun (at least 4-6 hours) | Weekly while establishing, then only during drought | Mildly toxic to pets |
| Caryopteris x clandonensis 'Dark Knight' | Direct sun (at least 4-6 hours) | Weekly during establishment, then sparingly in dry spells | Mildly toxic to pets |
| Caryopteris x clandonensis 'Heavenly Blue' | Direct sun (at least 4-6 hours) | Weekly while establishing, then only during prolonged drought | Mildly toxic to pets |
| Caryopteris x clandonensis 'Worcester Gold' | Direct sun (at least 4-6 hours) | Weekly while establishing, then only in drought | Mildly toxic to pets |
| Cascade Purple Aubrieta | Direct sun (at least 4-6 hours) | Weekly during active growth; minimal in summer dormancy | Pet-safe |
| Cascade White Trailing Lobelia | Bright indirect light (just back from a sunny window) | When the top 2 cm of compost is dry, roughly every 2-4 days (more frequent in hot weather) | Toxic to pets |
| Cascadia trailing petunia | Direct sun (at least 4-6 hours) | Every 2-3 days in warm weather; check daily in summer heat | Pet-safe |
| Castilian Heron's Bill | Direct sun (at least 4-6 hours) | Water sparingly every 10-14 days in the growing season; almost none from late autumn to spring | Mildly toxic to pets |
| Castlewellan Cypress | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days for young plants | Mildly toxic to pets |
| Cat's Claw Creeper | Direct sun (at least 4-6 hours) | Every 7–14 days; drought-tolerant when established | Mildly toxic to pets |
| Cat's-ear | Direct sun (at least 4-6 hours) | Low — very drought-tolerant once established | Mildly toxic to pets |
| Catalpa bignonioides | Direct sun (at least 4-6 hours) | Weekly while young; established trees are fairly drought-tolerant | Mildly toxic to pets |
| Catalpa bignonioides 'Aurea' | Direct sun (at least 4-6 hours) | Weekly while establishing; moderate drought tolerance when mature | Mildly toxic to pets |
| Catalpa speciosa | Direct sun (at least 4-6 hours) | Weekly when young; notably drought-tolerant once established | Mildly toxic to pets |
| Catasetum Orchid | Bright indirect light (just back from a sunny window) | Heavy in summer growth; none during winter dormancy | Mildly toxic to pets |
| Catawba rhododendron | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 7–14 days once established | Toxic to pets |
| Catawba Rhododendron 'Roseum Elegans' | Bright indirect light (just back from a sunny window) | About weekly, deeper in heat and drought; water when the top 3-5 cm of soil is dry | Toxic to pets |
| Catesby's Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist in spring; reduce after summer dormancy | Mildly toxic to pets |
| Catharanthus roseus 'Cora Cascade Strawberry' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-10 days | Toxic to pets |
| Catharanthus roseus 'Titan Polka Dot' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-10 days | Toxic to pets |
| Cathaya argyrophylla | Bright indirect light (just back from a sunny window) | When the top few cm of soil begins to dry, roughly every 5-7 days for young plants in growth | Mildly toxic to pets |
| Catlin's Giant Bugle | Medium indirect light (a couple of metres from a window) | Once or twice weekly during establishment; once weekly once established | Mildly toxic to pets |
| Catmint 'Walker's Low' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days during the growing season | Mildly toxic to pets |
| Cattleya 'Why Not' | Bright indirect light (just back from a sunny window) | When the bark dries, roughly every 5-7 days in growth | Pet-safe |
| Cattleya luteola | Bright indirect light (just back from a sunny window) | When the mix approaches dry, roughly every 5-7 days in growth | Pet-safe |
| Cattleya orchid | Bright indirect light (just back from a sunny window) | When the bark mix is nearly dry, every 5-10 days | Pet-safe |
| Cattleya walkeriana | Bright indirect light (just back from a sunny window) | When the mix is nearly dry, roughly every 5-7 days in growth; reduced after flowering | Pet-safe |
| Caucasian Comfrey | Medium indirect light (a couple of metres from a window) | Every 5–7 days during dry spells; self-sufficient in rainy climates | Mildly toxic to pets |
| Caucasian Draba | Direct sun (at least 4-6 hours) | Low — water only when soil is dry | Mildly toxic to pets |
| Caucasian Lily | Bright indirect light (just back from a sunny window) | Moderate — keep soil consistently moist but not waterlogged | Toxic to pets |
| Caucasian Rock Cress | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| Caucasian Scabious | Direct sun (at least 4-6 hours) | Water regularly while establishing and during dry spells, otherwise when the top few centimetres of soil are dry | Mildly toxic to pets |
| Cavatine pieris | Bright indirect light (just back from a sunny window) | Weekly; keep consistently moist | Toxic to pets |
| Ceanothus 'Concha' | Direct sun (at least 4-6 hours) | Water to establish, then little to no summer water once mature | Mildly toxic to pets |
| Ceanothus 'Puget Blue' | Direct sun (at least 4-6 hours) | Water to establish, then little to no summer water once mature | Mildly toxic to pets |
| Ceanothus 'Victoria' | Direct sun (at least 4-6 hours) | Water to establish in year one, then little to no summer water once settled | Mildly toxic to pets |
| Ceanothus americanus | Direct sun (at least 4-6 hours) | Weekly during the first season; rarely thereafter once established | Mildly toxic to pets |
| Ceanothus thyrsiflorus 'Skylark' | Direct sun (at least 4-6 hours) | Water to establish, then only occasional water; more summer-water tolerant than most ceanothus | Mildly toxic to pets |
| Cecile Brunner Climbing Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly while young; established plants are fairly drought-tolerant and need water mainly in dry spells | Pet-safe |
| Cedar of Lebanon | Direct sun (at least 4-6 hours) | Weekly during first 3 years; very drought-tolerant once established | Mildly toxic to pets |
| Cedar Sage | Medium indirect light (a couple of metres from a window) | Moderate; water when top 5 cm of soil is dry | Pet-safe |
| Celandine Poppy | Medium indirect light (a couple of metres from a window) | 2 times per week during spring and early summer; reduce as plant self-senesces | Mildly toxic to pets |
| Celosia (cockscomb) | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Pet-safe |
| Celosia argentea var. cristata 'Chief Mix' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-5 days | Pet-safe |
| Celosia argentea var. plumosa 'Fresh Look Yellow' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-5 days | Pet-safe |
| Celosia argentea var. spicata 'Cramer's Amazon' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-6 days once established | Pet-safe |
| Centaurea 'Amethyst in Snow' | Direct sun (at least 4-6 hours) | Weekly through the first season; established clumps are drought-tolerant | Pet-safe |
| Century Yellow Feather Celosia | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Cephalotaxus 'Fastigiata' | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, roughly weekly while establishing | Mildly toxic to pets |
| Cercidiphyllum japonicum | Bright indirect light (just back from a sunny window) | Weekly, keeping the soil consistently moist, especially in summer | Mildly toxic to pets |
| Cercidiphyllum japonicum 'Pendulum' | Bright indirect light (just back from a sunny window) | Weekly, keeping soil consistently moist, particularly in summer | Mildly toxic to pets |
| Cercis canadensis 'Forest Pansy' | Direct sun (at least 4-6 hours) | Weekly while establishing; deep soak during dry spells | Mildly toxic to pets |
| Cercis canadensis 'Lavender Twist' | Direct sun (at least 4-6 hours) | Weekly while establishing; supplement in drought | Mildly toxic to pets |
| Cercis siliquastrum | Direct sun (at least 4-6 hours) | Water regularly while young; rarely once established | Mildly toxic to pets |
| Ceropegia Sandersonii | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of mix is dry, roughly every 10-14 days in growth | Mildly toxic to pets |
| Chagual | Direct sun (at least 4-6 hours) | every 7–14 days in summer, rarely in winter | Pet-safe |
| Chain Fern | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 4-6 days | Mildly toxic to pets |
| Chalk Milkwort | Direct sun (at least 4-6 hours) | Infrequently; drought-tolerant once established | Mildly toxic to pets |
| Chamaerops Humilis 'Vulcano' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, every 7-14 days in summer | Pet-safe |
| Chamaerops Humilis Cerifera | Direct sun (at least 4-6 hours) | When the top few cm of soil are dry; drought-tolerant once established | Pet-safe |
| Chamomile | Direct sun (at least 4-6 hours) | When the top of the soil is dry, every 7-10 days | Toxic to pets |
| Chanticleer ornamental pear | Direct sun (at least 4-6 hours) | Weekly for first 2 years; drought-tolerant once established | Mildly toxic to pets |
| Chantilly Peach snapdragon | Direct sun (at least 4-6 hours) | Every 5–7 days; keep soil evenly moist but not waterlogged | Pet-safe |
| Charles Joly Lilac | Direct sun (at least 4-6 hours) | Every 7-10 days during dry periods; drought-tolerant once established | Mildly toxic to pets |
| Charlotte Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in growth; more in heat | Pet-safe |
| Cheddar Pink | Direct sun (at least 4-6 hours) | Sparingly — every 1–2 weeks in summer | Mildly toxic to pets |
| Cherokee Chief Dogwood | Bright indirect light (just back from a sunny window) | Weekly deep watering; more in summer drought | Pet-safe |
| Cherry Brandy Rudbeckia | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Cheshunt Pine | Bright indirect light (just back from a sunny window) | Water regularly to keep soil evenly moist; once or twice weekly in summer | Mildly toxic to pets |
| Chestnut-Flowered Sage | Medium indirect light (a couple of metres from a window) | Regular — keep soil evenly moist through the growing season | Mildly toxic to pets |
| Chiapas Sage | Medium indirect light (a couple of metres from a window) | Moderate — water when the top 2 cm of soil is dry | Pet-safe |
| Chilean Blue Crocus | Direct sun (at least 4-6 hours) | Regular watering during the spring growing season; completely dry from late spring through late autumn | Mildly toxic to pets |
| Chilean Jasmine | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 4-7 days in summer | Mildly toxic to pets |
| Chiltern Gentian | Direct sun (at least 4-6 hours) | Minimal supplementary watering needed; moderate natural rainfall is adequate | Mildly toxic to pets |
| Chin Cactus | Bright indirect light (just back from a sunny window) | When the soil is fully dry, about every 10-14 days in growth; none in winter | Pet-safe |
| China aster | Direct sun (at least 4-6 hours) | 2–3 times per week in warm weather; once per week in cool conditions | Pet-safe |
| China Fir | Direct sun (at least 4-6 hours) | Keep soil moist; water regularly while young, then deeply during dry spells once established | Mildly toxic to pets |
| China Girl dogwood | Bright indirect light (just back from a sunny window) | Weekly in first 2–3 years; every 1–2 weeks in dry periods once established | Mildly toxic to pets |
| China pink | Direct sun (at least 4-6 hours) | Every 5–7 days during active growth; reduce in cool weather | Mildly toxic to pets |
| Chincherinchee | Direct sun (at least 4-6 hours) | Regularly during active growth; dry or minimal during summer dormancy | Toxic to pets |
| Chinese Arborvitae | Direct sun (at least 4-6 hours) | Moderate — water regularly until established; drought-tolerant once established | Pet-safe |
| Chinese astilbe | Medium indirect light (a couple of metres from a window) | Once or twice per week; more in hot weather | Pet-safe |
| Chinese Astilbe 'Visions' | Bright indirect light (just back from a sunny window) | Keep soil reliably moist; water every 3-5 days in summer | Mildly toxic to pets |
| Chinese Astilbe 'Visions' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer; more drought-tolerant than most astilbes | Mildly toxic to pets |
| Chinese Douglas Fir | Direct sun (at least 4-6 hours) | Weekly when young; every 2 weeks once established | Pet-safe |
| Chinese Enkianthus | Bright indirect light (just back from a sunny window) | Regularly throughout the growing season | Mildly toxic to pets |
| Chinese Flowering Quince | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil approaches dry, often daily in summer heat | Mildly toxic to pets |
| Chinese Gentian | Direct sun (at least 4-6 hours) | Regular, keeping soil evenly moist throughout the growing season; reduce in winter | Mildly toxic to pets |
| Chinese Ground Orchid | Bright indirect light (just back from a sunny window) | Keep evenly moist during active growth (spring and summer), watering every 5-7 days; allow to dry out naturally in autumn as the plant goes dormant | Pet-safe |
| Chinese Hackberry | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil dries, often daily in summer | Mildly toxic to pets |
| Chinese Hemlock | Bright indirect light (just back from a sunny window) | Every 1–2 weeks when young; every 2–3 weeks once established | Pet-safe |
| Chinese Incense Cedar | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days for young plants | Mildly toxic to pets |
| Chinese Juniper | Direct sun (at least 4-6 hours) | Low to moderate; water regularly until established, then drought-tolerant | Mildly toxic to pets |
| Chinese Juniper 'Itoigawa' | Direct sun (at least 4-6 hours) | When the soil surface is approaching dry, then water thoroughly | Mildly toxic to pets |
| Chinese Lantern Plant | Direct sun (at least 4-6 hours) | Weekly during growing season; drought-tolerant once established | Toxic to pets |
| Chinese Larch | Direct sun (at least 4-6 hours) | Regular during establishment and growing season; reduced in dormancy | Pet-safe |
| Chinese peony | Direct sun (at least 4-6 hours) | Moderate — once or twice weekly during active growth; reduce significantly after foliage dies back in autumn | Mildly toxic to pets |
| Chinese Peony 'Sarah Bernhardt' | Direct sun (at least 4-6 hours) | Deeply once or twice a week during dry spells; reduce after foliage dies back | Toxic to pets |
| Chinese Plum Yew | Medium indirect light (a couple of metres from a window) | Keep evenly moist; weekly in dry spells, more while establishing | Mildly toxic to pets |
| Chinese Premna | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil dries, often daily in warm growth | Mildly toxic to pets |
| Chinese Redbud | Direct sun (at least 4-6 hours) | Every 7-10 days during the first two growing seasons; established plants roughly every 14 days in dry spells | Toxic to pets |
| Chinese Swamp Cypress | Direct sun (at least 4-6 hours) | Keep consistently moist to wet; tolerates prolonged inundation | Mildly toxic to pets |
| Chinese Sweetgum | Direct sun (at least 4-6 hours) | Weekly during the growing season; reduce in winter | Mildly toxic to pets |
| Chinese Trumpet Creeper | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days once established | Toxic to pets |
| Chinese Tupelo | Bright indirect light (just back from a sunny window) | Regularly during establishment; once or twice a week in dry spells | Pet-safe |
| Chinese Weeping Cypress | Direct sun (at least 4-6 hours) | Regular during establishment; drought-tolerant once mature | Pet-safe |
| Chinese White Pine | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry; allow slight drying between waterings | Mildly toxic to pets |
| Chinese Wild Ginger | Low light (north window or shaded room) | Water every 5–7 days, or when the top 2 cm of soil begins to dry | Mildly toxic to pets |
| Chinese witch hazel | Bright indirect light (just back from a sunny window) | Regularly during establishment (first 2–3 years); once established, during dry periods in summer | Mildly toxic to pets |
| Chinese Witch Hazel | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-14 days in the growing season | Mildly toxic to pets |
| Chinese woodbine | Medium indirect light (a couple of metres from a window) | Weekly; do not allow the root zone to dry out | Mildly toxic to pets |
| Chinese Yew | Medium indirect light (a couple of metres from a window) | Weekly during establishment; every 1–2 weeks once established | Toxic to pets |
| Chionodoxa luciliae | Direct sun (at least 4-6 hours) | Rainfall in most settings; rarely needs watering | Mildly toxic to pets |
| Chirita 'Aiko' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, about every 7-10 days | Mildly toxic to pets |
| Chirita micromusa | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the soil surface just begins to dry, roughly every 4-7 days | Pet-safe |
| Chirita sinensis | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Mildly toxic to pets |
| Chive-Leaved Thrift | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season; minimal in winter | Mildly toxic to pets |
| Chocolate Chip Bugle | Medium indirect light (a couple of metres from a window) | Once or twice weekly until established; once weekly thereafter | Mildly toxic to pets |
| Chocolate Cosmos | Direct sun (at least 4-6 hours) | Keep evenly moist through summer; water roughly weekly, more in heat, less once dormant | Pet-safe |
| Chocolate orchid | Bright indirect light (just back from a sunny window) | When the mix is nearly dry, roughly every 5-9 days | Pet-safe |
| Choisya 'Sundance' | Direct sun (at least 4-6 hours) | Water weekly while establishing, then only during extended dry periods | Mildly toxic to pets |
| Choisya 'White Dazzler' | Bright indirect light (just back from a sunny window) | Water weekly while establishing; mature plants need water only in dry spells | Mildly toxic to pets |
| Choisya ternata | Direct sun (at least 4-6 hours) | Water deeply once a week through the first two seasons, then only in prolonged dry spells | Mildly toxic to pets |
| Choisya x dewitteana 'Aztec Pearl' | Direct sun (at least 4-6 hours) | Water weekly through the first two years, then only in dry spells | Mildly toxic to pets |
| Christmas cactus | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is dry, every 7-10 days | Pet-safe |
| Christmas Orchid | Bright indirect light (just back from a sunny window) | When the bark dries, roughly every 5-7 days in growth | Pet-safe |
| Christmas Rose | Medium indirect light (a couple of metres from a window) | Keep evenly moist while establishing and during summer drought; established plants tolerate moderate dryness | Toxic to pets |
| Christmas Tree Cactus | Direct sun (at least 4-6 hours) | When the soil is fully dry, roughly every 14-21 days in the growing season and once a month or less in winter | Pet-safe |
| Chrysanthemum | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in active growth | Toxic to pets |
| Chrysanthemum 'Anastasia' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Chrysanthemum 'Bronze Elegance' | Direct sun (at least 4-6 hours) | Every 5-7 days when the top 2-3 cm of soil is dry; more frequently in hot weather | Toxic to pets |
| Chrysanthemum 'Cheryl Pride' | Direct sun (at least 4-6 hours) | Every 4-6 days, allowing the top 2-3 cm of soil to dry | Toxic to pets |
| Chrysanthemum 'Cottage Apricot' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Chrysanthemum 'Country Girl' | Direct sun (at least 4-6 hours) | Every 5-7 days in summer; reduce in autumn as growth slows | Toxic to pets |
| Chrysanthemum 'Emperor of China' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 7 days | Toxic to pets |
| Chrysanthemum 'Golden Cascade' | Direct sun (at least 4-6 hours) | Every 3-5 days for container-grown plants; every 5-7 days in the ground when the top 2-3 cm of soil is dry | Toxic to pets |
| Chrysanthemum 'Hillside Pink Sheffield' | Direct sun (at least 4-6 hours) | Every 5-7 days when the top 2-3 cm of soil is dry | Toxic to pets |
| Chrysanthemum 'Innocence' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Chrysanthemum 'Mei-kyo' | Direct sun (at least 4-6 hours) | Every 5-7 days when the top 2-3 cm of soil is dry | Toxic to pets |
| Chrysanthemum 'Pennine Alfie' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, every 5-7 days in the growing season | Toxic to pets |
| Chrysanthemum 'Ruby Mound' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Chrysanthemum 'Rumpelstiltskin' | Direct sun (at least 4-6 hours) | Every 5-7 days, allowing the top 2 cm to dry between waterings | Toxic to pets |
| Chrysanthemum 'Ryan's Daisy' | Direct sun (at least 4-6 hours) | Every 5-7 days; increase to every 3-4 days in containers during hot spells | Toxic to pets |
| Chrysanthemum 'Salmon Allouise' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Chrysanthemum 'Snowdon' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Chrysanthemum 'Time Piece' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Chrysanthemum 'Will's Wonderful' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, approximately every 5-7 days | Toxic to pets |
| Chrysanthemum 'Yellow John Wingfield' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Chrysanthemum 'Zeal Bronze' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Cilician Colchicum | Direct sun (at least 4-6 hours) | Rely on natural rainfall during growth; keep dry in summer dormancy (June–August) | Toxic to pets |
| Cilician Fir | Direct sun (at least 4-6 hours) | Moderate; drought-tolerant once established | Pet-safe |
| Cilician Meadow Saffron | Direct sun (at least 4-6 hours) | Sparingly; allow soil to dry between waterings, roughly every 14-21 days in active growth | Toxic to pets |
| Cilician Winter Aconite | Medium indirect light (a couple of metres from a window) | Moist during late winter and spring growth; dry to moderate when dormant | Toxic to pets |
| Cinco de Mayo Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week through the growing season, more in heat | Pet-safe |
| Cinderella Miniature Rose | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water when the top 2-3 cm is dry, roughly twice weekly and more in heat | Pet-safe |
| Clarke's Cranesbill | Bright indirect light (just back from a sunny window) | Regularly during establishment; once established, once a week in dry periods | Pet-safe |
| Clasping Sage | Bright indirect light (just back from a sunny window) | Weekly to fortnightly | Pet-safe |
| Claw Sage | Direct sun (at least 4-6 hours) | Water when the top 3–5 cm of soil feels dry | Pet-safe |
| Cleft Phlox | Direct sun (at least 4-6 hours) | Every 10–14 days when establishing; monthly once established in dry periods | Pet-safe |
| Cleistocactus baumannii | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly weekly in summer; sparingly in winter | Pet-safe |
| Clematis | Direct sun (at least 4-6 hours) | Keep evenly moist; water newly planted and container clematis frequently | Toxic to pets |
| Clematis 'Bill MacKenzie' | Direct sun (at least 4-6 hours) | Deeply about once a week while growing; less once established | Toxic to pets |
| Clematis 'Comtesse de Bouchaud' | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week in the growing season; more in heat or sandy soil | Toxic to pets |
| Clematis 'Doctor Ruppel' | Direct sun (at least 4-6 hours) | Deeply once or twice a week during the growing season; reduce in autumn and winter | Toxic to pets |
| Clematis 'Dr. Ruppel' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Clematis 'Duchess of Edinburgh' | Bright indirect light (just back from a sunny window) | Once or twice a week during the growing season | Toxic to pets |
| Clematis 'Ernest Markham' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about weekly in summer | Toxic to pets |
| Clematis 'Etoile Violette' | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week in the growing season | Toxic to pets |
| Clematis 'Fireworks' | Direct sun (at least 4-6 hours) | Once or twice a week in the growing season; reduce in autumn | Toxic to pets |
| Clematis 'General Sikorski' | Direct sun (at least 4-6 hours) | Once or twice a week during the growing season | Toxic to pets |
| Clematis 'H.F. Young' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil or compost is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Clematis 'Hagley Hybrid' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, about weekly in the growing season | Toxic to pets |
| Clematis 'Henryi' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, about weekly in summer | Toxic to pets |
| Clematis 'Jackmanii' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water deeply once or twice weekly in dry weather | Toxic to pets |
| Clematis 'Lasurstern' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil or compost is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Clematis 'Miss Bateman' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, about weekly in the growing season | Toxic to pets |
| Clematis 'Mrs N. Thompson' | Direct sun (at least 4-6 hours) | Once or twice a week during the growing season; reduce in cooler months | Toxic to pets |
| Clematis 'Multi Blue' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Clematis 'Nelly Moser' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water deeply once or twice a week in dry spells | Toxic to pets |
| Clematis 'Niobe' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about weekly in summer | Toxic to pets |
| Clematis 'Perle d'Azur' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 5-7 days during active growth | Toxic to pets |
| Clematis 'Piilu' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Clematis 'Polish Spirit' | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week through the growing season | Toxic to pets |
| Clematis 'Rebecca' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Clematis 'Rouge Cardinal' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Clematis 'Rubens' | Direct sun (at least 4-6 hours) | Once or twice a week during dry spells, especially the first two seasons | Toxic to pets |
| Clematis 'The President' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply once or twice a week in dry spells | Toxic to pets |
| Clematis 'Ville de Lyon' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly weekly in the growing season | Toxic to pets |
| Clematis 'Warszawska Nike' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about weekly in summer | Toxic to pets |
| Clematis 'Westerplatte' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Clematis armandii | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly weekly in the growing season | Toxic to pets |
| Clematis florida 'Sieboldii' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Clematis integrifolia | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week through the growing season | Toxic to pets |
| Clematis montana | Direct sun (at least 4-6 hours) | Water regularly while establishing; mature plants are fairly drought-tolerant | Toxic to pets |
| Clematis montana 'Grandiflora' | Direct sun (at least 4-6 hours) | Once or twice a week while establishing; drought-tolerant once mature | Toxic to pets |
| Clematis recta | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week in the growing season | Toxic to pets |
| Clematis tangutica | Direct sun (at least 4-6 hours) | Deeply about once a week in the growing season; less once established | Toxic to pets |
| Clematis viticella | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week through the growing season | Toxic to pets |
| Clethra alnifolia | Bright indirect light (just back from a sunny window) | Keep soil moist; water weekly or more in dry weather, tolerant of wet ground | Mildly toxic to pets |
| Clethra alnifolia 'Hummingbird' | Bright indirect light (just back from a sunny window) | Keep soil moist; water weekly or more in dry weather, tolerant of wet ground | Mildly toxic to pets |
| Clethra alnifolia 'Ruby Spice' | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water deeply 1-2 times weekly in the first two seasons and during drought | Mildly toxic to pets |
| Clethra barbinervis | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water deeply weekly in the first two seasons and during dry spells | Mildly toxic to pets |
| Cleveland Sage | Direct sun (at least 4-6 hours) | Very infrequent after establishment — once monthly or less in summer | Pet-safe |
| Climbing Fetterbush | Medium indirect light (a couple of metres from a window) | Frequent; keep consistently moist to wet | Toxic to pets |
| Climbing Hydrangea | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply weekly in the first 2-3 years and during dry spells | Toxic to pets |
| Climbing Iceberg Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season, more during heat | Pet-safe |
| Climbing Sundew | Bright indirect light (just back from a sunny window) | Tray method autumn–spring; bone dry summer dormancy | Mildly toxic to pets |
| Clivia | Bright indirect light (just back from a sunny window) | When the top 3 cm of soil is dry, roughly every 10-14 days | Toxic to pets |
| Clivia 'Belgian Hybrid' | Medium indirect light (a couple of metres from a window) | Water when the top few cm are dry in growth; keep nearly dry through the winter rest | Toxic to pets |
| Clivia 'Doris Joy' | Bright indirect light (just back from a sunny window) | When the top few cm are dry in growth (every 7-14 days); much less in the winter rest | Toxic to pets |
| Cloth of Gold Saxifrage | Medium indirect light (a couple of metres from a window) | Every 5–7 days; reduce in winter | Pet-safe |
| Cloud Nine Dogwood | Bright indirect light (just back from a sunny window) | Weekly during the growing season; reduce in winter | Mildly toxic to pets |
| Clouds of Perfume Woodland Phlox | Medium indirect light (a couple of metres from a window) | Weekly during the growing season; do not allow soil to dry out in summer | Pet-safe |
| Clubmoss cassiope | Bright indirect light (just back from a sunny window) | Regularly; soil should remain consistently moist throughout the growing season | Pet-safe |
| Clumping Blue Bamboo | Bright indirect light (just back from a sunny window) | Consistently moist throughout the growing season; water every 5–7 days or as needed to keep soil from drying out | Pet-safe |
| Clustered bellflower | Direct sun (at least 4-6 hours) | Weekly during dry spells; moderate water needs | Pet-safe |
| Clustered Freesia | Direct sun (at least 4-6 hours) | Moderate during growth; reduce to dry after dormancy | Pet-safe |
| Clustered Sanicle | Low light (north window or shaded room) | Every 1–2 weeks; maintain consistent moisture, never waterlogged | Mildly toxic to pets |
| Clustered Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days during the growing season; withhold entirely during dormancy | Pet-safe |
| Coast Redwood Bonsai | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil starts to dry, often daily in warm weather | Mildly toxic to pets |
| Coast Rock Cress | Direct sun (at least 4-6 hours) | Weekly in the growing season; reduce to monthly or less when summer-dormant | Pet-safe |
| Coastal Doghobble | Medium indirect light (a couple of metres from a window) | Every 5–7 days; regular deep watering essential in dry periods | Toxic to pets |
| Coastal Leucothoe | Medium indirect light (a couple of metres from a window) | Regular; keep evenly moist | Toxic to pets |
| Cobaea scandens | Direct sun (at least 4-6 hours) | Keep evenly moist through the growing season; water containers regularly | Mildly toxic to pets |
| Cobra Lily | Low light (north window or shaded room) | Keep evenly moist through the spring-to-summer growing season, watering when the surface begins to dry; reduce as the plant dies back to dormancy. | Toxic to pets |
| Cockleshell butterfly orchid | Bright indirect light (just back from a sunny window) | Weekly in growth; reduce in winter | Pet-safe |
| Cockleshell Orchid | Bright indirect light (just back from a sunny window) | When the bark mix is nearly dry, roughly every 5-8 days | Pet-safe |
| Cockscomb | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-6 days in summer | Pet-safe |
| Codonanthe crassifolia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Mildly toxic to pets |
| Codonanthe gracilis | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days | Mildly toxic to pets |
| Codonatanthus 'Sunset' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days | Mildly toxic to pets |
| Coelogyne cristata | Bright indirect light (just back from a sunny window) | Every 4-7 days in growth; sparingly during the winter rest | Pet-safe |
| Coelogyne flaccida | Bright indirect light (just back from a sunny window) | Every 4-7 days in growth; reduced over winter | Pet-safe |
| Coelogyne massangeana | Bright indirect light (just back from a sunny window) | Every 3-6 days in growth; slightly reduced but rarely dry in winter | Pet-safe |
| Cole's Prostrate Hemlock | Medium indirect light (a couple of metres from a window) | Every 1–2 weeks; do not allow soil to dry out | Pet-safe |
| Coleus | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, every 4-7 days | Toxic to pets |
| Colorado Blue Spruce | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; regular deep watering in first 2–3 years | Mildly toxic to pets |
| Coloratus Euonymus | Bright indirect light (just back from a sunny window) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| Columbia Lewisia | Bright indirect light (just back from a sunny window) | Moderate; reduce in late summer and winter | Mildly toxic to pets |
| Columbine | Medium indirect light (a couple of metres from a window) | Moderate; water during dry spells | Toxic to pets |
| Columbine 'McKana Giant' | Bright indirect light (just back from a sunny window) | Once or twice a week in dry weather; keep soil evenly moist during flowering | Toxic to pets |
| Columbine 'Nora Barlow' | Bright indirect light (just back from a sunny window) | Once or twice a week during dry spells; water stress shortens the flowering season | Toxic to pets |
| Column Aubrieta | Direct sun (at least 4-6 hours) | Weekly during spring growth; very sparingly in summer | Pet-safe |
| Columnae Snow-in-Summer | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Pet-safe |
| Columnar Douglas Fir | Direct sun (at least 4-6 hours) | Moderate during establishment; reduced once established | Pet-safe |
| Columnar English Oak | Direct sun (at least 4-6 hours) | Regular deep watering in the first 3-5 years; established trees are largely drought-tolerant | Mildly toxic to pets |
| Columnar Italian Cypress | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 14-21 days once established | Mildly toxic to pets |
| Columnea | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 5-7 days | Pet-safe |
| Columnea 'Aladdin's Lamp' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Columnea 'Inferno' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Columnea 'Light Prince' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Columnea 'Robin' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Columnea hirta | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Columnea linearis | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is just dry, roughly every 5-7 days in growth | Pet-safe |
| Columnea microphylla | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is just dry, roughly every 5-7 days in growth | Pet-safe |
| Comb Speedwell | Direct sun (at least 4-6 hours) | Every 2–3 weeks; very drought-tolerant | Pet-safe |
| Comfrey-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Moderate during the growing season; reduce significantly in winter. Established plants in the ground need watering only during extended dry spells. | Mildly toxic to pets |
| Common Angel's Trumpet | Direct sun (at least 4-6 hours) | Every 2–4 days in summer (soil should be consistently moist but not waterlogged) | Toxic to pets |
| Common Bird's-foot Trefoil | Direct sun (at least 4-6 hours) | Low once established | Mildly toxic to pets |
| Common Bistort | Medium indirect light (a couple of metres from a window) | Frequently — keep soil consistently moist | Mildly toxic to pets |
| Common Blanket Flower | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is fully dry, roughly every 10-14 days; very infrequent once established | Mildly toxic to pets |
| Common blue violet | Medium indirect light (a couple of metres from a window) | Every 5–10 days; tolerates wet soil | Pet-safe |
| Common box | Medium indirect light (a couple of metres from a window) | Weekly during establishment; monthly once established in the ground | Toxic to pets |
| Common Broom | Direct sun (at least 4-6 hours) | sparingly after establishment | Toxic to pets |
| Common Broomrape | Direct sun (at least 4-6 hours) | Wholly dependent on host plant via haustorial connection | Mildly toxic to pets |
| Common Bugle | Medium indirect light (a couple of metres from a window) | Moderate; consistent moisture preferred | Mildly toxic to pets |
| Common Butterwort | Bright indirect light (just back from a sunny window) | Keep permanently wet in the growing season; stand in shallow pure water | Mildly toxic to pets |
| Common Club-rush | Direct sun (at least 4-6 hours) | Permanently aquatic; plant at 30–150 cm (12–60 in) water depth | Pet-safe |
| Common Cordgrass | Direct sun (at least 4-6 hours) | Permanent wetland/tidal immersion | Pet-safe |
| Common Cow-wheat | Medium indirect light (a couple of metres from a window) | Moderate; keep soil evenly moist but never waterlogged | Mildly toxic to pets |
| Common Dog Violet | Medium indirect light (a couple of metres from a window) | Water occasionally; keep soil consistently moist but not waterlogged. | Pet-safe |
| common dogwood | Bright indirect light (just back from a sunny window) | Weekly in first season; largely self-sufficient once established | Mildly toxic to pets |
| Common Evening Primrose | Direct sun (at least 4-6 hours) | Every 10–14 days; highly tolerant of drought once established | Pet-safe |
| Common Foxglove | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water weekly in dry spells | Toxic to pets |
| Common Garden Tulip | Direct sun (at least 4-6 hours) | Naturally rainfall-dependent; water sparingly if dry after planting | Toxic to pets |
| Common Gladiolus | Direct sun (at least 4-6 hours) | Once or twice per week during active growth | Toxic to pets |
| Common Gorse | Direct sun (at least 4-6 hours) | rarely after establishment | Toxic to pets |
| Common Grape Hyacinth | Bright indirect light (just back from a sunny window) | Weekly in spring during active growth; dry during summer dormancy | Mildly toxic to pets |
| Common Grape Hyacinth | Direct sun (at least 4-6 hours) | Rainfall typically sufficient; water lightly once per week only in very dry springs | Toxic to pets |
| Common Heather | Direct sun (at least 4-6 hours) | Water weekly in dry spells for the first two seasons; established plants are moderately drought-tolerant | Pet-safe |
| Common Hepatica | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season; reduce in summer dormancy | Mildly toxic to pets |
| Common hollyhock | Direct sun (at least 4-6 hours) | Weekly when established; more in heat or drought | Mildly toxic to pets |
| Common Hyacinth | Direct sun (at least 4-6 hours) | Weekly when in active growth; withhold water during summer dormancy | Toxic to pets |
| Common immortelle | Direct sun (at least 4-6 hours) | Every 7–10 days; allow soil to dry between waterings | Pet-safe |
| Common Ironweed | Direct sun (at least 4-6 hours) | Moderate to high — keep soil moist | Mildly toxic to pets |
| Common Jasmine | Direct sun (at least 4-6 hours) | Water regularly while establishing and in dry spells; water when the top few cm of soil dries | Pet-safe |
| Common Juniper | Direct sun (at least 4-6 hours) | Low; water deeply but infrequently once established | Mildly toxic to pets |
| Common Knapweed | Direct sun (at least 4-6 hours) | Low — water only to establish | Mildly toxic to pets |
| Common Lilac | Direct sun (at least 4-6 hours) | Deeply once a week in the first year, then only in drought | Mildly toxic to pets |
| Common Lime | Direct sun (at least 4-6 hours) | Regular in first 2–3 years; occasional once established | Pet-safe |
| Common Mallow | Direct sun (at least 4-6 hours) | Low once established | Pet-safe |
| Common manzanita | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established — water sparingly in summer | Mildly toxic to pets |
| Common Milkweed | Direct sun (at least 4-6 hours) | Moderate; weekly when establishing, drought-tolerant once established | Toxic to pets |
| Common Milkwort | Direct sun (at least 4-6 hours) | Rarely; drought-tolerant once established | Mildly toxic to pets |
| Common peony | Direct sun (at least 4-6 hours) | Weekly during active growth; reduce after bloom | Mildly toxic to pets |
| Common Peony 'Rubra Plena' | Direct sun (at least 4-6 hours) | Deeply once or twice a week during dry spring and summer weather; minimal watering once dormant | Toxic to pets |
| Common Poppy | Direct sun (at least 4-6 hours) | Low once established; water seedlings until established | Toxic to pets |
| Common Quaking Grass | Direct sun (at least 4-6 hours) | Rarely; drought-tolerant once established | Pet-safe |
| Common Rhododendron | Bright indirect light (just back from a sunny window) | Weekly during dry periods; established plants are tolerant but flower best with consistent moisture | Toxic to pets |
| Common Rush | Direct sun (at least 4-6 hours) | Permanently wet or standing water to 15 cm (6 in) deep | Pet-safe |
| Common Saltmarsh Grass | Direct sun (at least 4-6 hours) | Tidal — periodic saltwater flooding | Pet-safe |
| Common Sea Lavender | Direct sun (at least 4-6 hours) | Low to moderate — drought-tolerant once established; tolerates periodic waterlogging | Pet-safe |
| Common Snowdrop | Medium indirect light (a couple of metres from a window) | Naturally moisture-retentive soil; supplemental watering in dry spells during growth | Toxic to pets |
| Common Spike-rush | Direct sun (at least 4-6 hours) | Permanently aquatic to waterlogged; plant at 0–30 cm (0–12 in) water depth | Pet-safe |
| Common Spotted Orchid | Bright indirect light (just back from a sunny window) | Relies on natural rainfall | Mildly toxic to pets |
| Common Star of Bethlehem | Direct sun (at least 4-6 hours) | Low; self-sufficient in a UK garden once established | Toxic to pets |
| Common Stork's Bill | Direct sun (at least 4-6 hours) | Naturally rain-fed; no supplemental watering needed for wild or meadow plantings | Mildly toxic to pets |
| Common teasel | Direct sun (at least 4-6 hours) | Rarely needs supplemental watering once established; water seedlings regularly | Pet-safe |
| Common Toadflax | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established; water only in the first season | Mildly toxic to pets |
| Common tobacco | Direct sun (at least 4-6 hours) | Every 3–5 days; maintain consistently moist soil | Toxic to pets |
| Common Tussock Grass | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; tolerates extended dry periods | Pet-safe |
| Common Water Hyacinth | Direct sun (at least 4-6 hours) | Free-floating aquatic — roots permanently submerged in open water | Pet-safe |
| Common Water Starwort | Medium indirect light (a couple of metres from a window) | Permanently submerged or marginal | Pet-safe |
| Common Water Starwort | Medium indirect light (a couple of metres from a window) | Fully submerged or surface-floating — permanent aquatic | Mildly toxic to pets |
| Common Witch Hazel | Medium indirect light (a couple of metres from a window) | Roughly every 7-10 days during establishment; established plants need watering every 10-14 days in dry periods | Mildly toxic to pets |
| Common Witch Hazel 'Arnold Promise' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry; keep evenly moist in the first years and during droughts | Mildly toxic to pets |
| Compact bog rosemary | Bright indirect light (just back from a sunny window) | Consistently moist; never allow to dry out | Toxic to pets |
| Compact White Fir | Direct sun (at least 4-6 hours) | Every 10-14 days during the first two years; drought-tolerant once established | Mildly toxic to pets |
| Compacta Holly | Direct sun (at least 4-6 hours) | Weekly deep watering when establishing, then every 7-14 days in dry periods | Toxic to pets |
| Compass Plant | Direct sun (at least 4-6 hours) | Every 2-4 weeks once established | Pet-safe |
| Compassion Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly when young; established plants when the top 5 cm of soil is dry | Pet-safe |
| Coneflower 'White Swan' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry; established plants are drought-tolerant once settled after the first season | Mildly toxic to pets |
| Confederate Rose | Direct sun (at least 4-6 hours) | Regularly during growth; deeply once or twice per week | Mildly toxic to pets |
| Congo cockatoo impatiens | Bright indirect light (just back from a sunny window) | Every 3–5 days; keep soil evenly moist | Pet-safe |
| Conica Jean's Dilly Spruce | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply weekly in the first two seasons, then during dry spells | Mildly toxic to pets |
| Constance Spry Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly while establishing; mature plants when the top few centimetres of soil dry | Pet-safe |
| Cook Pine | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Copper Iris | Direct sun (at least 4-6 hours) | Continuously moist to waterlogged | Mildly toxic to pets |
| Copper Rain Lily | Direct sun (at least 4-6 hours) | Low to moderate; rain-triggered | Toxic to pets |
| Cora XDR vinca | Direct sun (at least 4-6 hours) | Every 4–7 days once established; water young transplants more frequently | Toxic to pets |
| Coral Aloe | Direct sun (at least 4-6 hours) | When the soil is fully dry, roughly every 2-3 weeks in summer, sparingly in winter | Toxic to pets |
| Coral Bark Maple | Bright indirect light (just back from a sunny window) | When the top 3–5 cm of soil is dry, roughly every 5–7 days in summer; reduce in winter | Pet-safe |
| Coral bells | Medium indirect light (a couple of metres from a window) | Weekly during active growth; reduce in autumn and winter | Pet-safe |
| Coral Bells 'Caramel' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, around weekly in growth; more in heat and for containers | Pet-safe |
| Coral Bells 'Caramel' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil feels dry, roughly every 5-7 days during active growth | Pet-safe |
| Coral Bells 'Electra' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Pet-safe |
| Coral Bells 'Lime Rickey' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil feels dry, roughly every 5-7 days during active growth | Pet-safe |
| Coral Bells 'Obsidian' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly in growth; more in heat and for container plants | Pet-safe |
| Coral Bells 'Obsidian' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, approximately every 5-7 days during the growing season | Pet-safe |
| Coral Bells 'Palace Purple' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly in growth; more in heat and for container plants | Pet-safe |
| Coral Bells 'Palace Purple' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Pet-safe |
| Coral Cattleya | Bright indirect light (just back from a sunny window) | When the mix dries, roughly every 5-7 days in growth | Pet-safe |
| Coral Lily | Direct sun (at least 4-6 hours) | When top 2–3 cm of soil is dry | Toxic to pets |
| Coreopsis 'Jethro Tull' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 10-14 days once established | Pet-safe |
| Coreopsis 'Limerock Ruby' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Coreopsis 'Mercury Rising' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Coreopsis 'Moonbeam' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; weekly to establish, then sparingly | Pet-safe |
| Coreopsis 'Moonbeam' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days; very drought-tolerant once established | Pet-safe |
| Coreopsis 'Route 66' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Coreopsis 'Ruby Sunset' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Coreopsis 'Sienna Sunset' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Coreopsis 'Sunkiss' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Coreopsis 'Sunray' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Coreopsis 'Uptick Gold and Bronze' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Coreopsis 'Zagreb' | Direct sun (at least 4-6 hours) | Water to establish, then only in extended drought; drought-tolerant once settled | Pet-safe |
| Coreopsis grandiflora 'Early Sunrise' | Direct sun (at least 4-6 hours) | Water to establish, then only during drought; drought-tolerant once settled | Pet-safe |
| Coris-Leaved St John's Wort | Direct sun (at least 4-6 hours) | Low — water sparingly once established | Toxic to pets |
| Cork-Stemmed Passionflower | Direct sun (at least 4-6 hours) | Once or twice a week until established; less once mature | Pet-safe |
| Corky-Stemmed Passion Flower | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in summer | Mildly toxic to pets |
| Corn Marigold | Direct sun (at least 4-6 hours) | Low to moderate — water only in dry spells | Toxic to pets |
| Cornelia Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season, increasing in heat | Pet-safe |
| Cornflower | Direct sun (at least 4-6 hours) | Low to moderate — water during establishment only | Pet-safe |
| Cornish heath | Direct sun (at least 4-6 hours) | Weekly while establishing; every 2–3 weeks once settled | Pet-safe |
| Cornish Heath Mrs D.F. Maxwell | Direct sun (at least 4-6 hours) | Water weekly during dry spells, especially in the first two years | Pet-safe |
| Cornus kousa 'Miss Satomi' | Direct sun (at least 4-6 hours) | Water deeply weekly while establishing; supplement in dry spells | Pet-safe |
| Corrugated Sage | Bright indirect light (just back from a sunny window) | Weekly | Mildly toxic to pets |
| Corsage Orchid | Bright indirect light (just back from a sunny window) | When the mix has dried, roughly every 5-7 days in growth | Pet-safe |
| Corsican Heath | Direct sun (at least 4-6 hours) | Moderate; water occasionally once established | Mildly toxic to pets |
| Corsican Heron's Bill | Direct sun (at least 4-6 hours) | Low — allow soil to dry between waterings | Mildly toxic to pets |
| Cosmos | Direct sun (at least 4-6 hours) | Weekly watering | Pet-safe |
| Cosmos 'Sensation' | Direct sun (at least 4-6 hours) | Water young plants until established, then only in prolonged drought; drought-tolerant once rooted | Pet-safe |
| Cosmos bipinnatus 'Picotee' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, about every 7-10 days | Pet-safe |
| Cosmos bipinnatus 'Sensation White' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, about every 7-10 days | Pet-safe |
| Cosmos sulphureus 'Bright Lights' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, about every 7-10 days | Pet-safe |
| Cosmos sulphureus 'Klondike' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days once established | Pet-safe |
| Cosson's Germander | Direct sun (at least 4-6 hours) | Sparingly every 2–3 weeks in summer; minimal to none in winter | Mildly toxic to pets |
| Costa Rica Pitaya | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in summer; every 2-4 weeks in winter | Pet-safe |
| Cotinus coggygria 'Golden Spirit' | Direct sun (at least 4-6 hours) | Weekly while establishing; sparingly once mature | Mildly toxic to pets |
| Cotinus coggygria 'Grace' | Direct sun (at least 4-6 hours) | Weekly while establishing; rarely thereafter once rooted | Mildly toxic to pets |
| Cotinus obovatus | Direct sun (at least 4-6 hours) | Weekly during establishment; very rarely once mature | Mildly toxic to pets |
| Cotoneaster Bonsai | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil is dry, roughly every 1-3 days in summer | Mildly toxic to pets |
| Cotoneaster microphyllus | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil is dry, roughly every 1-3 days in summer | Mildly toxic to pets |
| Cow Parsley | Medium indirect light (a couple of metres from a window) | Moderate; water during dry spells in the first season | Mildly toxic to pets |
| Cowslip | Medium indirect light (a couple of metres from a window) | Twice weekly in active growth, reduce to once weekly when dormant in summer | Toxic to pets |
| Crabapple 'Evereste' | Direct sun (at least 4-6 hours) | Weekly during establishment and dry spells | Toxic to pets |
| Crabapple 'Hanagasa' | Direct sun (at least 4-6 hours) | When the top 2-3 cm is dry, frequently daily in summer and less in dormancy | Toxic to pets |
| Crabapple 'John Downie' | Direct sun (at least 4-6 hours) | Weekly while young and in summer drought | Toxic to pets |
| Crabapple Bonsai | Direct sun (at least 4-6 hours) | When the surface soil starts to dry, often once or twice daily in summer | Toxic to pets |
| Cramer's Amazon celosia | Direct sun (at least 4-6 hours) | Every 3–5 days | Pet-safe |
| Crane's Bill Stork's Bill | Direct sun (at least 4-6 hours) | Water lightly; allow the soil surface to dry between waterings | Mildly toxic to pets |
| Crataegus laevigata 'Paul's Scarlet' | Direct sun (at least 4-6 hours) | Water weekly for the first two seasons; established trees are very drought-tolerant | Pet-safe |
| Crataegus persimilis 'Prunifolia' | Direct sun (at least 4-6 hours) | Water weekly for the first two seasons; established trees are drought-tolerant | Pet-safe |
| Cream Wild Indigo | Direct sun (at least 4-6 hours) | Low; water weekly in first season only | Toxic to pets |
| Creeping Baby's Breath | Direct sun (at least 4-6 hours) | Once per week in dry spells; very little in winter | Mildly toxic to pets |
| Creeping Blue Blossom | Direct sun (at least 4-6 hours) | Every 7-10 days during the first growing season; established plants are very drought-tolerant and need supplemental watering only in prolonged dry summers | Mildly toxic to pets |
| Creeping Comfrey | Low light (north window or shaded room) | Every 7–14 days; largely self-sufficient once established | Mildly toxic to pets |
| Creeping Gaultheria | Medium indirect light (a couple of metres from a window) | Regularly; soil must not dry out | Toxic to pets |
| Creeping Globe Daisy | Direct sun (at least 4-6 hours) | Every 2–3 weeks when actively growing; minimal in winter | Pet-safe |
| Creeping Globularia | Direct sun (at least 4-6 hours) | Every 14 days during active growth; virtually none in winter. | Mildly toxic to pets |
| Creeping Juniper | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; weekly during the first growing season | Mildly toxic to pets |
| Creeping Little Bluestem | Direct sun (at least 4-6 hours) | Minimal once established; rainfall usually sufficient on native sites | Pet-safe |
| Creeping Mazus | Bright indirect light (just back from a sunny window) | Every 3–5 days; prefers consistently moist soil | Mildly toxic to pets |
| Creeping New Zealand Cranesbill | Direct sun (at least 4-6 hours) | Every 7–10 days in the growing season; minimal in winter | Pet-safe |
| Creeping Phlox | Direct sun (at least 4-6 hours) | Weekly when establishing; every 2 weeks once established | Mildly toxic to pets |
| Creeping Phlox 'Blue Ridge' | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Creeping Sage | Bright indirect light (just back from a sunny window) | Weekly during the growing season | Pet-safe |
| Creeping snowberry | Medium indirect light (a couple of metres from a window) | Regular; keep moist | Mildly toxic to pets |
| Creeping Speedwell | Bright indirect light (just back from a sunny window) | Moderate; water when the top 2–3 cm of soil begins to dry | Pet-safe |
| Creeping Willow | Direct sun (at least 4-6 hours) | frequent — keep soil reliably moist | Mildly toxic to pets |
| Creeping Woodland Phlox | Medium indirect light (a couple of metres from a window) | Weekly; maintain consistent moisture | Mildly toxic to pets |
| Crenate Orchid Cactus | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 7-14 days in the growing season; reduce to once every 3-4 weeks in winter | Pet-safe |
| Crested Floating Heart | Direct sun (at least 4-6 hours) | Permanently aquatic; maintain 10–60 cm water depth | Mildly toxic to pets |
| Crested Gentian | Direct sun (at least 4-6 hours) | Regular; keep soil consistently moist during the growing season | Mildly toxic to pets |
| Crested Iris | Medium indirect light (a couple of metres from a window) | Moderate — keep evenly moist | Toxic to pets |
| Crested Phlomis | Direct sun (at least 4-6 hours) | Once every 2–3 weeks in summer, barely at all in winter | Mildly toxic to pets |
| Cretan Arum | Direct sun (at least 4-6 hours) | Moderate during autumn–spring active growth; completely dry in summer | Toxic to pets |
| Crimean Linden | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 2–3 weeks in dry summers once mature | Pet-safe |
| Crimson and Gold quince | Bright indirect light (just back from a sunny window) | Weekly when newly planted; established plants largely rain-fed in temperate climates | Mildly toxic to pets |
| Crimson Flag Lily | Direct sun (at least 4-6 hours) | Consistently moist throughout the growing season | Toxic to pets |
| Crimson Water Lily | Direct sun (at least 4-6 hours) | Permanently aquatic — crown submerged 15–50 cm (6–20 in) below water surface | Pet-safe |
| Crimson-Spot Rock Rose | Direct sun (at least 4-6 hours) | Every 3–4 weeks once established; weekly in the first growing season | Mildly toxic to pets |
| Crippsii Hinoki Cypress | Direct sun (at least 4-6 hours) | Every 5-7 days while establishing, then when the top few cm of soil dry | Mildly toxic to pets |
| Crocosmia × crocosmiiflora 'Emily McKenzie' | Direct sun (at least 4-6 hours) | Weekly during growth and flowering in dry weather; ease off as foliage dies back | Mildly toxic to pets |
| Crocosmia × crocosmiiflora 'Jackanapes' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; water through dry spells in the growing season | Mildly toxic to pets |
| Crocosmia × crocosmiiflora 'Lucifer' | Direct sun (at least 4-6 hours) | Weekly during active growth and flowering in dry spells; reduce after foliage dies back | Mildly toxic to pets |
| Crocosmia × crocosmiiflora 'Solfatare' | Direct sun (at least 4-6 hours) | Weekly during growth and flowering in dry spells; reduce as foliage dies back | Mildly toxic to pets |
| Crocosmia masoniorum | Direct sun (at least 4-6 hours) | Weekly during growth and flowering in dry weather; taper off as foliage dies back | Mildly toxic to pets |
| Crocus | Direct sun (at least 4-6 hours) | Natural rainfall | Mildly toxic to pets |
| Crocus 'Jeanne d'Arc' | Direct sun (at least 4-6 hours) | Rely on natural rainfall; water only during a dry autumn after planting or a droughty spring | Mildly toxic to pets |
| Crocus 'Pickwick' | Direct sun (at least 4-6 hours) | Depend on rainfall; supplemental water only during a dry spell right after autumn planting or active spring growth | Mildly toxic to pets |
| Crocus chrysanthus 'Cream Beauty' | Direct sun (at least 4-6 hours) | Rely on rainfall; water only during a dry establishment period after planting or a droughty spring | Mildly toxic to pets |
| Crocus tommasinianus 'Ruby Giant' | Direct sun (at least 4-6 hours) | Rainfall-reliant; water only briefly during a dry autumn establishment or droughty early spring | Mildly toxic to pets |
| Cross Gentian | Bright indirect light (just back from a sunny window) | Water regularly until established; drought-tolerant thereafter | Mildly toxic to pets |
| Cross-leaved heath | Direct sun (at least 4-6 hours) | Frequently — keep soil consistently moist to wet | Pet-safe |
| Cross-leaved Heath Alba Mollis | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 5–7 days in dry spells | Pet-safe |
| Crossandra (firecracker flower) | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil starts to dry, often every 4-7 days in growth | Pet-safe |
| Crossvine | Bright indirect light (just back from a sunny window) | Weekly when young; established plants are drought-tolerant | Mildly toxic to pets |
| Crosswort | Medium indirect light (a couple of metres from a window) | Low to moderate — rainfall sufficient in UK | Mildly toxic to pets |
| Crown Brodiaea | Direct sun (at least 4-6 hours) | Moderate during autumn-to-spring growth; completely dry from flowering through to early autumn | Mildly toxic to pets |
| Crown Cactus | Direct sun (at least 4-6 hours) | When the soil is fully dry, roughly every 10-14 days in growth; none from late autumn through winter | Pet-safe |
| Crown Imperial | Direct sun (at least 4-6 hours) | Regular in spring growth phase; dry to minimal in summer dormancy | Toxic to pets |
| Crown of Thorns | Direct sun (at least 4-6 hours) | Every 1-2 weeks in growth; sparingly in winter | Toxic to pets |
| Crown Vetch | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Mildly toxic to pets |
| Crystal Palace lobelia | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, typically every 2-3 days in summer | Toxic to pets |
| Crystal Palace Lobelia | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil feels dry, roughly every 3-5 days | Toxic to pets |
| Crystal White narrowleaf zinnia | Direct sun (at least 4-6 hours) | Every 5–7 days; drought tolerant once established | Pet-safe |
| Cuban Lily | Direct sun (at least 4-6 hours) | Moderate in autumn through spring; restrict in summer | Toxic to pets |
| Cuckooflower | Medium indirect light (a couple of metres from a window) | Moderate to high — keep moist at all times | Mildly toxic to pets |
| Cucumber Tree Magnolia | Bright indirect light (just back from a sunny window) | Every 2–3 weeks when established; more frequently during active growth in summer | Pet-safe |
| Cunninghamia 'Glauca' | Direct sun (at least 4-6 hours) | Keep soil moist; water regularly while young, then deeply in dry spells once established | Mildly toxic to pets |
| Cup Plant | Direct sun (at least 4-6 hours) | Keep soil moist; water deeply in dry spells, every 5-7 days | Mildly toxic to pets |
| Cupani sweet pea | Direct sun (at least 4-6 hours) | Every 3–5 days in warm growing conditions; adjust for rainfall | Toxic to pets |
| Cupcake Miniature Rose | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Pet-safe |
| Cupcakes Blush cosmos | Direct sun (at least 4-6 hours) | Every 5–7 days; drought tolerant once established | Pet-safe |
| Cuphea hyssopifolia | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 5-7 days | Mildly toxic to pets |
| Curly Pondweed | Bright indirect light (just back from a sunny window) | Fully submerged; grows in 30 cm to 2 m of water | Pet-safe |
| Curly-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; weekly during the first growing season | Mildly toxic to pets |
| Curved-Flower Sage | Bright indirect light (just back from a sunny window) | Regular, allowing surface to partially dry between waterings | Mildly toxic to pets |
| Cushion Baby's Breath | Direct sun (at least 4-6 hours) | Every 2–4 weeks in growing season; very sparingly or not at all in winter | Mildly toxic to pets |
| Cushion Draba | Direct sun (at least 4-6 hours) | Sparingly; soil must dry between waterings | Pet-safe |
| Cushion Sandwort | Direct sun (at least 4-6 hours) | Sparingly; allow to dry between waterings | Pet-safe |
| Cushion Thrift | Direct sun (at least 4-6 hours) | Very low — drought-tolerant once established | Mildly toxic to pets |
| Cusick's Camas | Bright indirect light (just back from a sunny window) | Regular during autumn through spring growth; reduces naturally as foliage senesces in early summer | Mildly toxic to pets |
| Cusick's Camas | Bright indirect light (just back from a sunny window) | Regular moisture during spring growth; tolerates drier conditions after foliage dies back in summer | Mildly toxic to pets |
| Cusp Blazing Star | Direct sun (at least 4-6 hours) | Every 2-3 weeks once established; avoid irrigation in winter | Pet-safe |
| Cut-Leaved Cranesbill | Direct sun (at least 4-6 hours) | Moderate; keep soil moist during spring and summer | Pet-safe |
| Cutleaf coneflower | Direct sun (at least 4-6 hours) | Twice weekly during establishment; weekly or more in dry spells once established | Pet-safe |
| Cutleaf Fleabane | Direct sun (at least 4-6 hours) | Every 10–14 days during active growth; very little in winter | Pet-safe |
| Cutleaf Toothwort | Medium indirect light (a couple of metres from a window) | Moderate during the active growth period (March–May); none needed once dormant in summer. | Pet-safe |
| Cyclamen | Bright indirect light (just back from a sunny window) | When the soil surface feels dry, roughly every 5-10 days in bloom | Toxic to pets |
| Cyclamen 'Victoria' | Bright indirect light (just back from a sunny window) | When the top of the compost feels dry, roughly every 5-7 days while in growth | Toxic to pets |
| Cyclamen-flowered Daffodil | Bright indirect light (just back from a sunny window) | Regular during autumn to late spring; dry summer dormancy | Toxic to pets |
| Cylindric Blazing Star | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; regular watering during establishment | Pet-safe |
| Cylindrical Rock Jasmine | Direct sun (at least 4-6 hours) | Very sparingly; almost none in winter | Pet-safe |
| Cymbidium 'Red Beauty' | Bright indirect light (just back from a sunny window) | Every 4-7 days in growth; every 10-14 days in winter | Pet-safe |
| Cymbidium 'Sarah Jean' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, about every 5-7 days, drier in winter | Pet-safe |
| Cymbidium 'Showgirl' | Bright indirect light (just back from a sunny window) | Every 4-7 days in growth; every 10-14 days in winter | Pet-safe |
| Cymbidium devonianum | Bright indirect light (just back from a sunny window) | Every 5-7 days in growth; reduce to every 10-14 days in winter | Pet-safe |
| Cymbidium erythrostylum | Bright indirect light (just back from a sunny window) | Every 5-7 days in growth; every 10-14 days in winter | Pet-safe |
| Cymbidium Golden Elf 'Sundust' | Bright indirect light (just back from a sunny window) | Every 4-7 days in growth; every 10-14 days in cooler months | Pet-safe |
| Cymbidium tracyanum | Bright indirect light (just back from a sunny window) | Every 3-6 days in growth; keep evenly moist in summer | Pet-safe |
| Cyperus longus | Direct sun (at least 4-6 hours) | Keep the soil wet to saturated; grow in shallow water up to about 5-15 cm or in permanently boggy ground | Mildly toxic to pets |
| Cyperus Sedge | Bright indirect light (just back from a sunny window) | Permanently wet; shallow water up to 15 cm deep | Pet-safe |
| Cyprus Cedar | Direct sun (at least 4-6 hours) | Every 10-14 days when young; established trees rely mostly on rainfall | Mildly toxic to pets |
| Cyprus Cedar | Direct sun (at least 4-6 hours) | Infrequently; drought-tolerant once established | Mildly toxic to pets |
| Cystopteris bulbifera | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water when the surface begins to dry, roughly every 3-6 days in growth | Mildly toxic to pets |
| Cystopteris fragilis | Medium indirect light (a couple of metres from a window) | Keep evenly moist while in growth, watering when the top 1-2 cm of soil dries, roughly every 4-7 days | Mildly toxic to pets |
| Daffodil | Direct sun (at least 4-6 hours) | Rely on rainfall in autumn-spring; keep dry in summer | Toxic to pets |
| Daffodil | Bright indirect light (just back from a sunny window) | Moderate during active growth (autumn–spring); dry during summer dormancy | Toxic to pets |
| Dagger-Leaf Rush | Bright indirect light (just back from a sunny window) | Frequent to constant — soil must remain moist to wet at all times | Pet-safe |
| Daghestan Sage | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Mildly toxic to pets |
| Dahlia | Direct sun (at least 4-6 hours) | Deep watering 2-3 times per week, more in heat | Toxic to pets |
| Dahlia | Direct sun (at least 4-6 hours) | Twice weekly during active growth | Mildly toxic to pets |
| Dahlia 'Ace Summer Sunset' | Direct sun (at least 4-6 hours) | Water deeply 2-3 times a week in summer once established, more during heat | Toxic to pets |
| Dahlia 'Akita' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in warm weather | Toxic to pets |
| Dahlia 'American Dawn' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week, more during heat | Toxic to pets |
| Dahlia 'Bishop of Dover' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of soil dries out, roughly every 3-5 days in warm weather | Mildly toxic to pets |
| Dahlia 'Bishop of Llandaff' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week in active growth; keep evenly moist | Mildly toxic to pets |
| Dahlia 'Bishop of Llandaff' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Bishop of Oxford' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of soil is dry, typically every 3-5 days in summer | Mildly toxic to pets |
| Dahlia 'Boom Boom White' | Direct sun (at least 4-6 hours) | Water deeply 2-3 times a week through summer once established, more in heat | Toxic to pets |
| Dahlia 'Bora Bora' | Direct sun (at least 4-6 hours) | Deep watering 2-3 times weekly once established, more in heat | Mildly toxic to pets |
| Dahlia 'Breakout' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week, more in heat | Toxic to pets |
| Dahlia 'Cafe au Lait' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Camano Ariel' | Direct sun (at least 4-6 hours) | Every 5-7 days, or when the top 2-3 cm of soil feels dry | Toxic to pets |
| Dahlia 'Contraste' | Direct sun (at least 4-6 hours) | Every 5-7 days, or when the top 2-3 cm of soil is dry | Toxic to pets |
| Dahlia 'Decorette Rose' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days; container plants may need daily watering in hot weather | Toxic to pets |
| Dahlia 'El Trasno' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of soil feels dry, approximately every 3-5 days in summer | Mildly toxic to pets |
| Dahlia 'Fire Magic' | Direct sun (at least 4-6 hours) | Every 5-7 days once established, or when the top 2-3 cm of soil is dry | Toxic to pets |
| Dahlia 'Gallery Art Deco' | Direct sun (at least 4-6 hours) | Deeply 2-3 times weekly, more for containers | Mildly toxic to pets |
| Dahlia 'Ginger Snap' | Direct sun (at least 4-6 hours) | Water deeply 2-3 times a week in summer once established, more in heat | Toxic to pets |
| Dahlia 'Hollyhill Black Beauty' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week, more in heat | Toxic to pets |
| Dahlia 'Jazz' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Karma Choc' | Direct sun (at least 4-6 hours) | Deeply 2-3 times weekly once growing strongly | Mildly toxic to pets |
| Dahlia 'Karma Naomi' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week once established, more in heat | Toxic to pets |
| Dahlia 'Labyrinth' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week, increasing in heat | Toxic to pets |
| Dahlia 'Mingus Tina' | Direct sun (at least 4-6 hours) | Every 3-4 days during active growth, more frequently in hot weather | Toxic to pets |
| Dahlia 'Mrs Eileen' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Mystery Day' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Mystic Illusion' | Direct sun (at least 4-6 hours) | Deeply 2-3 times weekly when in growth | Mildly toxic to pets |
| Dahlia 'Orange Mullet' | Direct sun (at least 4-6 hours) | Every 5-7 days, or when the top 2-3 cm of soil is dry | Toxic to pets |
| Dahlia 'Penhill Dark Monarch' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Penhill Watermelon' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week, more during heat | Toxic to pets |
| Dahlia 'Purple Taiheijo' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Rip City' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Dahlia 'Senior Ball' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days; more often in hot weather | Toxic to pets |
| Dahlia 'Soda Fountain' | Direct sun (at least 4-6 hours) | Every 3-4 days in warm weather; less in cool spells | Toxic to pets |
| Dahlia 'Thomas Edison' | Direct sun (at least 4-6 hours) | Deeply 2-3 times weekly during active growth | Mildly toxic to pets |
| Dahurian Juniper | Direct sun (at least 4-6 hours) | Every 3–4 weeks once established; more frequent in the first season | Mildly toxic to pets |
| Dahurian Larch | Direct sun (at least 4-6 hours) | Weekly during establishment; minimal once established | Pet-safe |
| Dainty Bess Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly during growth | Pet-safe |
| Dalmatian Cranesbill | Direct sun (at least 4-6 hours) | Every 7–10 days during the growing season; minimal in winter | Pet-safe |
| Dancing Lady Orchid | Bright indirect light (just back from a sunny window) | When the mix begins to dry, roughly every 4-6 days in growth | Pet-safe |
| Danford Iris | Direct sun (at least 4-6 hours) | Moderate in late winter and early spring; dry in summer | Toxic to pets |
| Daphne cneorum | Direct sun (at least 4-6 hours) | Water when the top few centimetres of soil are dry; keep evenly moist but sharply drained | Toxic to pets |
| Daphne laureola | Low light (north window or shaded room) | Weekly while establishing; rarely once established | Toxic to pets |
| Daphne mezereum | Bright indirect light (just back from a sunny window) | Water when the top few centimetres of soil are dry; keep evenly moist, never waterlogged | Toxic to pets |
| Daphne odora | Bright indirect light (just back from a sunny window) | Water when the top few centimetres of soil are dry; keep evenly moist, never soggy | Toxic to pets |
| Daphne odora 'Aureomarginata' | Bright indirect light (just back from a sunny window) | Water when the top few centimetres of soil are dry; keep evenly moist but never wet | Toxic to pets |
| Daphne x burkwoodii 'Carol Mackie' | Bright indirect light (just back from a sunny window) | Water when the top few centimetres of soil are dry; keep evenly moist, never waterlogged | Toxic to pets |
| Darcey Bussell Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in growth; container plants more often | Pet-safe |
| Darcy's Sage | Direct sun (at least 4-6 hours) | Regular to moderate — allow soil surface to dry between waterings | Mildly toxic to pets |
| Dark Beauty heather | Direct sun (at least 4-6 hours) | Weekly during the first season; as needed once established | Pet-safe |
| Dark-purple Primulina | Medium indirect light (a couple of metres from a window) | When the top third of compost feels dry | Mildly toxic to pets |
| Darley Dale heath | Direct sun (at least 4-6 hours) | Weekly while establishing; every 2–3 weeks once established | Pet-safe |
| Darley Dale Heath Furzey | Direct sun (at least 4-6 hours) | Water weekly in dry spells; reduce in winter unless the soil is very dry | Pet-safe |
| Darwin's barberry | Direct sun (at least 4-6 hours) | Every 1–2 weeks during establishment; drought-tolerant once established | Mildly toxic to pets |
| Darwin's Barberry | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Darwin's Slipper | Bright indirect light (just back from a sunny window) | Moderately — water when the top of the compost is barely dry | Mildly toxic to pets |
| Darwin's Slipper Plant | Bright indirect light (just back from a sunny window) | When the top of the growing medium dries slightly | Mildly toxic to pets |
| David viburnum | Bright indirect light (just back from a sunny window) | Once or twice weekly when establishing; monthly once mature | Mildly toxic to pets |
| Davidia involucrata | Bright indirect light (just back from a sunny window) | Weekly in dry spells, especially the first few years | Mildly toxic to pets |
| Dawn Redwood 'Gold Rush' | Direct sun (at least 4-6 hours) | When the surface soil starts to dry; keep consistently moist, every 5-10 days | Mildly toxic to pets |
| Dawn Redwood 'Ogon' | Direct sun (at least 4-6 hours) | When the topsoil begins to dry; keep evenly moist, every 5-10 days | Mildly toxic to pets |
| Dawn Redwood Bonsai | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil starts to dry, often daily or twice daily in summer | Mildly toxic to pets |
| Dawn viburnum | Bright indirect light (just back from a sunny window) | Weekly in the first two seasons; every 2–3 weeks once established | Mildly toxic to pets |
| Daybreak Red Stripe Treasure Flower | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days | Pet-safe |
| Daylily | Direct sun (at least 4-6 hours) | Weekly; keep moist in the first season | Toxic to pets |
| Daylily 'Autumn Minaret' | Direct sun (at least 4-6 hours) | Every 7-14 days during active growth; minimal in winter dormancy | Toxic to pets |
| Daylily 'Bitsy' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season; reduce to once every 2-3 weeks as foliage dies back | Toxic to pets |
| Daylily 'Black-eyed Stella' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Bumble Bee' | Direct sun (at least 4-6 hours) | Every 7-10 days in active growth; every 2-3 weeks once dormant | Toxic to pets |
| Daylily 'Catherine Woodbery' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season; every 2-3 weeks during dormancy | Toxic to pets |
| Daylily 'Chicago Apache' | Direct sun (at least 4-6 hours) | Roughly every 7-10 days during the growing season; reduce to every 2-3 weeks in winter dormancy | Toxic to pets |
| Daylily 'Chorus Line' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth and rebloom cycles; reduce to every 2-3 weeks in dormancy | Toxic to pets |
| Daylily 'Crimson Pirate' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; every 2-3 weeks in dormancy | Toxic to pets |
| Daylily 'Double River Wye' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; every 2-3 weeks during dormancy | Toxic to pets |
| Daylily 'Fragrant Returns' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; consistent moisture supports multiple rebloom cycles | Toxic to pets |
| Daylily 'Frans Hals' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during the growing season | Toxic to pets |
| Daylily 'Golden Zebra' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season; reduce to every 2-3 weeks as foliage dies back | Toxic to pets |
| Daylily 'Happy Returns' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during active growth | Toxic to pets |
| Daylily 'Hyperion' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; every 2-3 weeks in dormancy | Toxic to pets |
| Daylily 'Ice Carnival' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; every 2-3 weeks in dormancy | Toxic to pets |
| Daylily 'Joan Senior' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; every 1-2 weeks in winter (evergreen foliage requires some moisture year-round in mild climates) | Toxic to pets |
| Daylily 'Little Grapette' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; every 2-3 weeks in dormancy | Toxic to pets |
| Daylily 'Luxury Lace' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Mary Todd' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Midnight Magic' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Miss Amelia' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Mozhart' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Nile Crane' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Orange Velvet' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Pan for Gold' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Pardon Me' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Pearl Lewis' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Prairie Blue Eyes' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Primal Scream' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7 days in summer | Toxic to pets |
| Daylily 'Purple d'Oro' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Red Hot Returns' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Rosy Returns' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Ruby Spider' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7 days during summer | Toxic to pets |
| Daylily 'Sanctuary' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Daylily 'Siloam Double Classic' | Direct sun (at least 4-6 hours) | Roughly every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'Siloam Virginia Henson' | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'So Lovely' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'Stafford' | Direct sun (at least 4-6 hours) | Every 7-10 days, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'Stella de Oro' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during the growing season | Toxic to pets |
| Daylily 'Stoke Poges' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'Strawberry Candy' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'Tiger Bloodlines' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'Tuscawilla Snowfall' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'When I Dream' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Daylily 'Wind Frills' | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season, or when the top 5 cm of soil is dry | Toxic to pets |
| Dazzler cosmos | Direct sun (at least 4-6 hours) | Weekly until established; every 10–14 days once established | Pet-safe |
| Deciduous Azalea 'Gibraltar' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply 1-2 times weekly through summer, more in heat | Toxic to pets |
| Deer Grass | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; monthly or less in cool months | Pet-safe |
| Degroot's Spire Arborvitae | Direct sun (at least 4-6 hours) | Two to three times weekly while young; weekly once established | Mildly toxic to pets |
| Delphinium 'Black Knight' | Direct sun (at least 4-6 hours) | Every 3-5 days in growth; keep soil consistently moist, never dry | Toxic to pets |
| Delphinium 'Galahad' | Direct sun (at least 4-6 hours) | Every 3-5 days in growth; keep the soil consistently moist, never dry | Toxic to pets |
| Delphinium 'Magic Fountains' | Direct sun (at least 4-6 hours) | Keep evenly moist; water deeply 2-3 times weekly in growth | Toxic to pets |
| Delphinium 'Pacific Giant' | Direct sun (at least 4-6 hours) | Keep consistently moist; water deeply 2-3 times weekly in growth | Toxic to pets |
| Delphinium grandiflorum 'Blue Butterfly' | Direct sun (at least 4-6 hours) | Every 4-7 days; keep soil moist but well-drained, avoiding extremes | Toxic to pets |
| Delta Pure White pansy | Bright indirect light (just back from a sunny window) | Every 2–3 days in warm weather; weekly in cool, wet conditions | Pet-safe |
| Dendrobium 'Berry Oda' | Bright indirect light (just back from a sunny window) | When the bark is nearly dry, roughly every 5-7 days in growth | Pet-safe |
| Dendrobium 'Emma White' | Bright indirect light (just back from a sunny window) | When the bark mix nears dry, roughly every 5-7 days in growth | Pet-safe |
| Dendrobium loddigesii | Bright indirect light (just back from a sunny window) | Frequently in growth, roughly every 4-6 days; sparingly through the winter rest | Pet-safe |
| Dendrobium orchid | Bright indirect light (just back from a sunny window) | When the bark approaches dryness, every 5-10 days in summer | Pet-safe |
| Dendrobium phalaenopsis | Bright indirect light (just back from a sunny window) | When the mix is approaching dry, roughly every 5-7 days in growth | Pet-safe |
| Densiformis Yew | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, roughly weekly while establishing | Toxic to pets |
| Deodar Cedar | Direct sun (at least 4-6 hours) | Weekly during first 2 years; drought-tolerant once established | Mildly toxic to pets |
| Deodar Cedar 'Karl Fuchs' | Direct sun (at least 4-6 hours) | Every 1-2 weeks while establishing, then sparingly | Mildly toxic to pets |
| Deparia acrostichoides | Low light (north window or shaded room) | Keep evenly moist; water when the top 2 cm starts to dry, roughly every 4-7 days in growth | Pet-safe |
| Desdemona Ligularia | Medium indirect light (a couple of metres from a window) | Constantly moist to wet; never let it dry out — water generously in dry spells, sometimes daily in heat | Mildly toxic to pets |
| Desert Rose | Direct sun (at least 4-6 hours) | Every 7-10 days in active growth; roughly monthly in winter dormancy | Toxic to pets |
| Deshojo Japanese Maple | Bright indirect light (just back from a sunny window) | Keep consistently moist; frequently daily in summer | Mildly toxic to pets |
| Deutschland Astilbe | Bright indirect light (just back from a sunny window) | Keep soil consistently moist to wet; water when the top 2-3 cm dries, about every 3-5 days in summer | Mildly toxic to pets |
| Deutzia 'Elegantissima' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during the growing season | Pet-safe |
| Deutzia 'Magnifica' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Deutzia 'Mont Rose' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Deutzia 'Nikko' | Direct sun (at least 4-6 hours) | Weekly in the first season; during dry spells once established | Pet-safe |
| Deutzia 'Nikko' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during active growth | Mildly toxic to pets |
| Deutzia gracilis | Direct sun (at least 4-6 hours) | Weekly in the first year, then during dry spells | Pet-safe |
| Deutzia scabra 'Plena' | Direct sun (at least 4-6 hours) | Weekly while establishing, then in dry spells | Pet-safe |
| Deutzia x elegantissima 'Rosealind' | Direct sun (at least 4-6 hours) | Weekly while establishing, then during droughts | Pet-safe |
| Devil's-bit Scabious | Bright indirect light (just back from a sunny window) | Regular; keep soil consistently moist throughout spring and summer | Mildly toxic to pets |
| Diablo Orange Cosmos | Direct sun (at least 4-6 hours) | When the top 3–5 cm of soil is dry, roughly every 7–10 days | Pet-safe |
| Diana Clare Pulmonaria | Low light (north window or shaded room) | Keep soil evenly moist; water every 4-6 days in dry spells, more in pots | Mildly toxic to pets |
| Diana Rose of Sharon | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days in summer | Pet-safe |
| Diane's Gold Brunnera | Low light (north window or shaded room) | Keep soil evenly moist; water when the top 2-3 cm dries, roughly every 4-6 days in heat | Mildly toxic to pets |
| Dianthus 'Doris' | Direct sun (at least 4-6 hours) | Water when the top few cm of soil is dry; drought-tolerant once established | Toxic to pets |
| Dianthus 'Mrs Sinkins' | Direct sun (at least 4-6 hours) | Water when the top few cm of soil is dry; drought-tolerant once established | Toxic to pets |
| Dianthus deltoides | Direct sun (at least 4-6 hours) | Water when soil is dry; drought-tolerant once established | Toxic to pets |
| Dianthus gratianopolitanus 'Firewitch' | Direct sun (at least 4-6 hours) | Water when soil is dry; very drought-tolerant once established | Toxic to pets |
| Diapensia-Like Saxifrage | Direct sun (at least 4-6 hours) | Very low — water sparingly in spring and summer; virtually none in winter | Pet-safe |
| Diascia 'Wink Coral Pink' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 2-3 days in warm weather | Pet-safe |
| Diascia barberae 'Piccadilly' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 2-3 days in warm weather | Pet-safe |
| Dicentra formosa 'Luxuriant' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil begins to dry, roughly every 5-7 days | Toxic to pets |
| Didissandra uniflora | Medium indirect light (a couple of metres from a window) | When the top 1-2 cm of mix begins to dry, roughly every 4-7 days | Mildly toxic to pets |
| Digitalis 'Camelot Cream' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly weekly in dry spells | Toxic to pets |
| Digyna Sweet Box | Low light (north window or shaded room) | Every 10-14 days during the first two growing seasons; established plants are drought-tolerant and need watering only in extended dry spells | Mildly toxic to pets |
| Dilys Cranesbill | Medium indirect light (a couple of metres from a window) | Water once a week during dry spells; largely self-sufficient once established in UK conditions | Pet-safe |
| Dimpled Trout Lily | Medium indirect light (a couple of metres from a window) | Consistently moist from emergence to dormancy (late winter to late spring) | Mildly toxic to pets |
| Dinnerplate Dahlia 'Café au Lait' | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week in active growth once sprouted; keep evenly moist | Mildly toxic to pets |
| Dioscorides' Arum | Bright indirect light (just back from a sunny window) | Moderate during active growth (autumn–spring); dry off completely in summer | Toxic to pets |
| Dipladenia (Mandevilla) | Direct sun (at least 4-6 hours) | Every 3-5 days in summer growth; sparingly in winter | Mildly toxic to pets |
| Disocactus phyllanthoides | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days in growth | Mildly toxic to pets |
| Divine Orange New Guinea Impatiens | Bright indirect light (just back from a sunny window) | Water when the top 2-3 cm of compost is dry, roughly every 2-3 days in warm weather; containers in full sun may need daily watering in peak summer | Mildly toxic to pets |
| Dog Rose | Direct sun (at least 4-6 hours) | Weekly during the first growing season; rarely once established | Pet-safe |
| Dog's Tooth Violet | Medium indirect light (a couple of metres from a window) | Moderate during active growth; minimal when dormant | Mildly toxic to pets |
| Dogwood | Medium indirect light (a couple of metres from a window) | Low to moderate — water during establishment; drought-tolerant thereafter | Mildly toxic to pets |
| Dogwood 'Eddie's White Wonder' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply in dry spells | Mildly toxic to pets |
| Dolce Blackcurrant Heuchera | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Pet-safe |
| Don Juan Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season, more in heat | Pet-safe |
| Dotted Blazing Star | Direct sun (at least 4-6 hours) | Every 3–4 weeks once established; moderate during first season | Pet-safe |
| Double Angel's Trumpet | Direct sun (at least 4-6 hours) | Every 2–4 days in summer (keep soil consistently moist) | Toxic to pets |
| Double Bloodroot | Medium indirect light (a couple of metres from a window) | Every 5–7 days during spring growth; withhold or greatly reduce during summer dormancy | Toxic to pets |
| Double Click Cranberries Cosmos | Direct sun (at least 4-6 hours) | When the top 3–5 cm of soil is dry, roughly every 7 days in summer | Pet-safe |
| Double Click Snow Puff cosmos | Direct sun (at least 4-6 hours) | Weekly once established; more frequent in heat | Pet-safe |
| Double Delight Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Double King Cup | Bright indirect light (just back from a sunny window) | Permanently moist to standing water 0–5 cm deep | Mildly toxic to pets |
| Double Knock Out Rose | Direct sun (at least 4-6 hours) | About 2.5 cm weekly, deep watering | Pet-safe |
| Double Marsh Marigold | Bright indirect light (just back from a sunny window) | Permanently moist to standing water 0–5 cm deep | Mildly toxic to pets |
| Double Pink Oleander | Direct sun (at least 4-6 hours) | Water weekly when establishing; drought-tolerant once established | Toxic to pets |
| Double-Flowered Bloodroot | Medium indirect light (a couple of metres from a window) | Moderate in spring; reduce as plant approaches dormancy in summer | Toxic to pets |
| doublefile viburnum | Bright indirect light (just back from a sunny window) | Weekly when young; every 10–14 days once established | Mildly toxic to pets |
| Doublefile Viburnum 'Mariesii' | Direct sun (at least 4-6 hours) | Deep soak when the top 5 cm of soil dries, roughly weekly in the first two seasons | Pet-safe |
| Douglas Fir | Direct sun (at least 4-6 hours) | Regular during first 3 years; established trees tolerate moderate drought in cool climates | Mildly toxic to pets |
| Douglas Phlox | Direct sun (at least 4-6 hours) | Weekly when establishing; twice monthly once established | Mildly toxic to pets |
| Douglas's Phlox | Direct sun (at least 4-6 hours) | Low to moderate — allow soil to partially dry between waterings | Mildly toxic to pets |
| Douglas's Sinningia | Bright indirect light (just back from a sunny window) | Allow top 2 cm to dry between waterings | Pet-safe |
| Dove's-Foot Cranesbill | Direct sun (at least 4-6 hours) | Low; water only during extended drought | Pet-safe |
| Downy Oak | Direct sun (at least 4-6 hours) | Rarely once established; weekly in first 1–2 years | Mildly toxic to pets |
| Downy Painted Cup | Direct sun (at least 4-6 hours) | Infrequently, once established | Mildly toxic to pets |
| Downy Phlox | Direct sun (at least 4-6 hours) | Weekly when establishing; every 2-3 weeks when established | Mildly toxic to pets |
| Downy Rock Jasmine | Direct sun (at least 4-6 hours) | Very sparingly; nearly dry between waterings | Mildly toxic to pets |
| Downy Sage | Direct sun (at least 4-6 hours) | Moderate; water when the top 5 cm of soil is dry | Mildly toxic to pets |
| Downy Yellow Violet | Medium indirect light (a couple of metres from a window) | Regular; keep evenly moist | Pet-safe |
| Dracunculus canariensis | Direct sun (at least 4-6 hours) | Water in autumn-through-spring growth when the top few cm dry; keep dry during summer dormancy | Toxic to pets |
| Dragon Arum | Direct sun (at least 4-6 hours) | Water moderately in spring growth, letting the top few cm dry; keep dry once foliage dies down in summer | Toxic to pets |
| Dragon Heart Cranesbill | Bright indirect light (just back from a sunny window) | Moderate; water during dry spells | Mildly toxic to pets |
| Dragon Wing Begonia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 5-7 days; more in heat | Toxic to pets |
| Dragon's Blood Stonecrop | Direct sun (at least 4-6 hours) | When soil is dry, about every 10-14 days in summer; minimal in winter | Pet-safe |
| Drooping Clivia | Bright indirect light (just back from a sunny window) | When top 3-4 cm of soil is dry, roughly every 7-12 days in growth | Toxic to pets |
| Drooping Leucothoe | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season; weekly in dry spells | Toxic to pets |
| Drooping Star of Bethlehem | Bright indirect light (just back from a sunny window) | Low; rainfall usually sufficient in temperate gardens | Toxic to pets |
| Drooping Star of Bethlehem | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry during active growth, roughly every 7-10 days | Toxic to pets |
| Drooping Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist throughout spring; can tolerate slightly drier conditions in summer dormancy. | Mildly toxic to pets |
| Dropwort | Direct sun (at least 4-6 hours) | Infrequent; drought-tolerant once established | Mildly toxic to pets |
| Drosera anglica | Direct sun (at least 4-6 hours) | Keep constantly saturated; stand in 1-3 cm of pure water through the growing season | Pet-safe |
| Drosera intermedia | Direct sun (at least 4-6 hours) | Keep permanently saturated; stand in 1-3 cm of pure water at all times during growth | Pet-safe |
| Druce's Cranesbill | Bright indirect light (just back from a sunny window) | Water during establishment; once established largely drought-tolerant | Pet-safe |
| Drummond's Aster | Medium indirect light (a couple of metres from a window) | Low to moderate | Pet-safe |
| Dryopteris affinis 'Cristata' | Low light (north window or shaded room) | Keep soil consistently moist; water deeply during dry spells, roughly weekly in summer | Pet-safe |
| Dryopteris carthusiana | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist, watering when the top 1-2 cm dries, roughly every 4-6 days | Mildly toxic to pets |
| Dryopteris championii | Low light (north window or shaded room) | Keep evenly moist; water deeply in dry spells, roughly weekly in summer heat | Pet-safe |
| Dryopteris dilatata | Medium indirect light (a couple of metres from a window) | Keep soil moist, watering when the top 2-3 cm dries, roughly every 5-7 days; established plants tolerate short dry spells | Mildly toxic to pets |
| Dryopteris dilatata 'Crispa Whiteside' | Medium indirect light (a couple of metres from a window) | Keep soil moist, watering when the top 2-3 cm dries, roughly every 5-7 days; established clumps tolerate brief dryness | Mildly toxic to pets |
| Dryopteris filix-mas 'Linearis Polydactyla' | Low light (north window or shaded room) | Keep soil consistently moist; water during dry spells so it never dries out | Mildly toxic to pets |
| Dryopteris goldiana | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Dryopteris intermedia | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist, watering when the top 2-3 cm dries, roughly every 5-7 days; established plants take brief dry spells | Mildly toxic to pets |
| Dryopteris ludoviciana | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 4-6 days | Pet-safe |
| Dryopteris tokyoensis | Low light (north window or shaded room) | Keep constantly moist to wet; never allow to dry out, watering as often as needed in summer | Pet-safe |
| Dryopteris uniformis | Low light (north window or shaded room) | Keep evenly moist; water deeply during dry spells, roughly weekly in summer | Pet-safe |
| Dusky Coral Pea | Direct sun (at least 4-6 hours) | Low once established; moderate during establishment | Mildly toxic to pets |
| Dusty zenobia | Bright indirect light (just back from a sunny window) | Consistently moist — water deeply and regularly, especially in summer heat | Toxic to pets |
| Dutch Iris | Direct sun (at least 4-6 hours) | Moderate during growth; dry in summer dormancy | Toxic to pets |
| Dutchman's Breeches | Medium indirect light (a couple of metres from a window) | Every 3-5 days in spring; none needed once dormant | Toxic to pets |
| Dutchman's pipe | Bright indirect light (just back from a sunny window) | Every 5–7 days during the growing season; less in cool dormancy. | Toxic to pets |
| Dwarf Alberta Spruce | Direct sun (at least 4-6 hours) | Every 5-7 days when establishing; deep soak when the top few cm of soil dry out | Pet-safe |
| Dwarf Astilbe 'Pumila' | Bright indirect light (just back from a sunny window) | Keep soil moist; water every 3-5 days in summer, more in heat | Mildly toxic to pets |
| Dwarf Bearded Iris | Direct sun (at least 4-6 hours) | Weekly during active growth; minimal in summer dormancy | Mildly toxic to pets |
| Dwarf Birch | Direct sun (at least 4-6 hours) | Regular moisture; do not allow to dry out, especially in summer | Pet-safe |
| Dwarf blue rhododendron | Bright indirect light (just back from a sunny window) | Every 7–14 days in the growing season; sparingly in winter | Toxic to pets |
| Dwarf Blue Spruce | Direct sun (at least 4-6 hours) | Every 7-10 days when young; deep, infrequent watering once established | Pet-safe |
| Dwarf Cape Primrose | Bright indirect light (just back from a sunny window) | every 5–8 days in the growing season, every 10–14 days in winter | Pet-safe |
| Dwarf Chin Cactus | Bright indirect light (just back from a sunny window) | When soil is completely dry, roughly every 10-14 days in summer; once every 4-6 weeks in winter | Pet-safe |
| Dwarf Coast Redwood | Direct sun (at least 4-6 hours) | Every 1–2 weeks; more in summer heat | Pet-safe |
| Dwarf Crocus | Direct sun (at least 4-6 hours) | Very low — dry Mediterranean dormancy essential; water only at planting and rely on winter rainfall | Mildly toxic to pets |
| Dwarf Edraianthus | Direct sun (at least 4-6 hours) | Low — allow to dry thoroughly between waterings | Mildly toxic to pets |
| Dwarf Golden Oriental Arborvitae | Direct sun (at least 4-6 hours) | Moderate — weekly when young, reduced once established | Toxic to pets |
| Dwarf Golden Oriental Arborvitae | Direct sun (at least 4-6 hours) | Once per week when the top 2-3 cm of soil is dry; more frequently in hot, dry summers | Toxic to pets |
| Dwarf Hinoki Cypress | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days depending on season | Mildly toxic to pets |
| Dwarf Indigo Bush | Direct sun (at least 4-6 hours) | Establish with occasional deep watering for the first season; essentially no supplemental water needed once the taproot is developed | Pet-safe |
| Dwarf Japanese Yew | Medium indirect light (a couple of metres from a window) | Moderate — drought-tolerant once established | Toxic to pets |
| Dwarf Korean Lilac | Direct sun (at least 4-6 hours) | Weekly while establishing, then every 1-2 weeks in dry spells | Pet-safe |
| Dwarf Lady's Mantle | Bright indirect light (just back from a sunny window) | Weekly during the growing season; established plants tolerate some drought | Pet-safe |
| Dwarf Lewisia | Direct sun (at least 4-6 hours) | Moderate during spring growth; completely dry in summer | Pet-safe |
| Dwarf Mountain Laurel Elf | Bright indirect light (just back from a sunny window) | Regular; maintain even moisture | Toxic to pets |
| Dwarf Pampas Grass | Direct sun (at least 4-6 hours) | Moderate; drought-tolerant once established | Mildly toxic to pets |
| Dwarf Pieris | Bright indirect light (just back from a sunny window) | Regular; keep evenly moist | Toxic to pets |
| Dwarf Snowberry | Bright indirect light (just back from a sunny window) | Regularly, keeping soil consistently moist | Toxic to pets |
| Dwarf Solomon's Seal | Medium indirect light (a couple of metres from a window) | Every 5–7 days during active growth; less when dormant | Mildly toxic to pets |
| Dwarf Trillium | Low light (north window or shaded room) | Keep soil consistently moist from spring emergence until dormancy; minimal watering once dormant | Mildly toxic to pets |
| Dwarf Tulip | Direct sun (at least 4-6 hours) | Sparingly; water at planting then only if soil dries out completely; cease watering after foliage dies back | Toxic to pets |
| Dwarf Whitestripe Bamboo | Bright indirect light (just back from a sunny window) | Consistently moist; water every 4–6 days during the growing season, reducing in autumn and winter | Pet-safe |
| Eared Sage | Bright indirect light (just back from a sunny window) | Weekly in summer, less in winter | Pet-safe |
| Early Goldenrod | Direct sun (at least 4-6 hours) | Low to moderate — drought-tolerant once established | Pet-safe |
| Early Purple Orchid | Medium indirect light (a couple of metres from a window) | Moist in spring; reduce significantly once summer dormancy begins | Mildly toxic to pets |
| Early Squill | Direct sun (at least 4-6 hours) | Water during active growth; keep drier in summer | Toxic to pets |
| East Himalayan Fir | Direct sun (at least 4-6 hours) | Regularly during establishment; drought-tolerant once mature | Pet-safe |
| Easter Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3cm of compost dries, roughly weekly in growth | Pet-safe |
| Easter Lily | Bright indirect light (just back from a sunny window) | When top 2–3 cm of soil is dry | Toxic to pets |
| Easter Lily Cactus | Direct sun (at least 4-6 hours) | When the top of the soil dries, roughly weekly to fortnightly in summer; keep almost dry in winter | Pet-safe |
| Easter Lily Cactus Clump | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 10-14 days in summer | Pet-safe |
| Easter Orchid | Bright indirect light (just back from a sunny window) | When the bark dries, roughly every 5-7 days in growth | Pet-safe |
| Eastern Bee Balm | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during the growing season | Pet-safe |
| Eastern Cyclamen | Medium indirect light (a couple of metres from a window) | Minimal in summer dormancy; rely on rainfall during autumn–spring growth | Toxic to pets |
| Eastern Everlasting | Direct sun (at least 4-6 hours) | Low — water only when the top 2 cm of soil is dry; drought-tolerant once established | Mildly toxic to pets |
| Eastern Hemlock | Medium indirect light (a couple of metres from a window) | Weekly during establishment; regular moisture required long-term | Pet-safe |
| Eastern Red Cedar | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established; water young transplants for 1–2 seasons | Mildly toxic to pets |
| Eastern Red Columbine | Medium indirect light (a couple of metres from a window) | Water when the top 3-5 cm of soil dries, roughly weekly | Mildly toxic to pets |
| Eastern Skunk Cabbage | Low light (north window or shaded room) | Continuously waterlogged; tolerates standing water | Toxic to pets |
| Eaton's Firecracker | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; minimal winter irrigation | Pet-safe |
| Eccremocarpus scaber | Direct sun (at least 4-6 hours) | Keep evenly moist through the growing season; water container plants regularly | Mildly toxic to pets |
| Echinacea 'After Midnight' | Direct sun (at least 4-6 hours) | Once or twice weekly during establishment; once every 10–14 days when fully established | Pet-safe |
| Echinacea 'Baby White Swan' | Direct sun (at least 4-6 hours) | Once or twice a week in year one; once every 10–14 days when established | Pet-safe |
| Echinacea 'Cheyenne Spirit' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; weekly while establishing, then mainly in drought | Pet-safe |
| Echinacea 'Cheyenne Spirit' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-14 days | Mildly toxic to pets |
| Echinacea 'Coconut Lime' | Direct sun (at least 4-6 hours) | Once or twice a week in the first year; once a week or less when fully established | Pet-safe |
| Echinacea 'Green Envy' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-14 days once established | Mildly toxic to pets |
| Echinacea 'Harvest Moon' | Direct sun (at least 4-6 hours) | Every 7-10 days once established; weekly during the first season | Pet-safe |
| Echinacea 'Hot Papaya' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Echinacea 'Hula Dancer' | Direct sun (at least 4-6 hours) | When the top 5-6 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Echinacea 'Magnus' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about weekly until established | Pet-safe |
| Echinacea 'Pink Double Delight' | Direct sun (at least 4-6 hours) | Every 7-10 days once established; more frequently during the first growing season | Pet-safe |
| Echinacea 'Pixie Meadowbrite' | Direct sun (at least 4-6 hours) | Once or twice a week during establishment; every 10–14 days when established | Pet-safe |
| Echinacea 'PowWow Wild Berry' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Echinacea 'Ruby Star' | Direct sun (at least 4-6 hours) | Once or twice a week during the first growing season; deeply once a week or less when established | Pet-safe |
| Echinacea 'Sunset' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-14 days once established | Mildly toxic to pets |
| Echinacea 'Tomato Soup' | Direct sun (at least 4-6 hours) | Once or twice a week during the first growing season; every 10–14 days once established | Pet-safe |
| Echinacea 'Virgin' | Direct sun (at least 4-6 hours) | Once or twice a week for the first growing season; once weekly to once every two weeks when established | Pet-safe |
| Echinacea 'White Swan' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about weekly until established | Pet-safe |
| Echinocereus coccineus | Direct sun (at least 4-6 hours) | When soil is bone-dry in growth, roughly every 10-14 days; none over winter | Pet-safe |
| Echinocereus engelmannii | Direct sun (at least 4-6 hours) | When soil is fully dry in growing season, about every 10-14 days; keep dry in winter | Pet-safe |
| Echinocereus pectinatus | Direct sun (at least 4-6 hours) | When soil is fully dry, roughly every 10-14 days in active growth; none in winter | Pet-safe |
| Echinocereus rigidissimus | Direct sun (at least 4-6 hours) | When the mix is fully dry, roughly every 12-16 days in growth; none in winter | Pet-safe |
| Echinops bannaticus 'Taplow Blue' | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water new plants until settled | Pet-safe |
| Echinops ritro | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water new plants until rooted | Pet-safe |
| Echinops ritro 'Veitch's Blue' | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water young plants until rooted | Pet-safe |
| Echinopsis huascha | Direct sun (at least 4-6 hours) | Soak-and-dry; roughly every 10-14 days in active growth, none in winter | Pet-safe |
| Ecuador Angel's Trumpet | Direct sun (at least 4-6 hours) | Every 2–4 days in summer (consistent moisture essential) | Toxic to pets |
| Edelweiss | Direct sun (at least 4-6 hours) | Every 2–3 weeks; reduce to almost nothing in winter | Pet-safe |
| Eden Valley bell heather | Direct sun (at least 4-6 hours) | Weekly when establishing; every 2–3 weeks once established | Pet-safe |
| Edging lobelia | Bright indirect light (just back from a sunny window) | Every 2–3 days in warm weather; every 5–7 days in cool conditions | Toxic to pets |
| Eglantyne Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly through the growing season, more in heat | Pet-safe |
| Egyptian Star Flower | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry | Mildly toxic to pets |
| Eichhornia crassipes | Direct sun (at least 4-6 hours) | Free-floating on warm, still or slow water; keep the pond topped up | Pet-safe |
| Elegant clarkia | Direct sun (at least 4-6 hours) | Every 7–14 days; drought-tolerant once established | Pet-safe |
| Elephant Ears 'Bressingham White' | Medium indirect light (a couple of metres from a window) | Every 7-14 days; established plants are relatively drought-tolerant but perform best with consistent moisture | Mildly toxic to pets |
| Elephant Ears Bergenia | Medium indirect light (a couple of metres from a window) | Every 7–14 days in summer; reduce to once a month or less in winter | Pet-safe |
| Elina Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season; more in heat | Pet-safe |
| Elizabeth Magnolia | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2 weeks in dry periods once mature | Mildly toxic to pets |
| Elk Blue Rush | Bright indirect light (just back from a sunny window) | Frequent to constant — keep soil consistently moist or wet | Pet-safe |
| Ellwoodii False Cypress | Direct sun (at least 4-6 hours) | Keep evenly moist; water deeply weekly while establishing, then during dry spells | Toxic to pets |
| Embothrium coccineum | Direct sun (at least 4-6 hours) | Keep the root zone evenly moist; water every 5-10 days in dry or hot spells, particularly while establishing | Mildly toxic to pets |
| Emerald Blue Creeping Phlox | Direct sun (at least 4-6 hours) | Every 7–10 days during the growing season; drought-tolerant once established (second year onward) | Pet-safe |
| Emerald Gaiety Euonymus | Bright indirect light (just back from a sunny window) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| Emerald Green Arborvitae | Direct sun (at least 4-6 hours) | Deeply 2-3 times per week when establishing; weekly once rooted in | Mildly toxic to pets |
| Emerald Green Arborvitae | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days for young plants | Mildly toxic to pets |
| Emerald n Gold Euonymus | Bright indirect light (just back from a sunny window) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| Emperor Tulip | Direct sun (at least 4-6 hours) | Rainfall-dependent during growth; summer dry period essential | Toxic to pets |
| Empress of India Nasturtium | Direct sun (at least 4-6 hours) | When the top 3–5 cm of soil is dry, roughly every 7–10 days | Mildly toxic to pets |
| Empress Wu Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 4-6 days in growth | Toxic to pets |
| Encore Azalea 'Autumn Twist' | Bright indirect light (just back from a sunny window) | About 2-3 times per week while establishing, then weekly; water when the top 2-3 cm of soil is dry | Toxic to pets |
| Encrusted Saxifrage | Direct sun (at least 4-6 hours) | Every 10–14 days in the growing season; rarely in winter | Pet-safe |
| Encyclia tampensis | Bright indirect light (just back from a sunny window) | When roots and medium are nearly dry, about every 3-5 days in growth | Pet-safe |
| Endura Scarlet Verbena | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-8 days | Toxic to pets |
| Engelmann Spruce | Direct sun (at least 4-6 hours) | Regular — keep soil consistently moist, especially in the first 3 years after planting | Pet-safe |
| English Bluebell | Medium indirect light (a couple of metres from a window) | Moderate; naturally moist in spring, drier in summer | Toxic to pets |
| English Yew Bonsai | Bright indirect light (just back from a sunny window) | When the top 2-3 cm is dry, around every 2-4 days in summer and less in winter | Toxic to pets |
| Entire-leaved Primrose | Direct sun (at least 4-6 hours) | Every 7–10 days in spring; minimal in summer and winter | Mildly toxic to pets |
| Envy Green Zinnia | Direct sun (at least 4-6 hours) | When the top 2–4 cm of soil feels dry, roughly every 5–7 days | Pet-safe |
| Epidendrum ibaguense | Direct sun (at least 4-6 hours) | When the top of the medium feels nearly dry, roughly every 4-6 days in growth | Pet-safe |
| Episcia 'Cleopatra' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil begins to dry, roughly every 5-7 days | Pet-safe |
| Episcia 'Moss Agate' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is dry, roughly every 4-7 days | Pet-safe |
| Episcia 'Pink Acajou' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, about every 5-7 days | Pet-safe |
| Episcia 'Silver Skies' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, about every 5-7 days | Pet-safe |
| Episcia reptans | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is dry, roughly every 4-7 days | Pet-safe |
| Equisetum hyemale | Direct sun (at least 4-6 hours) | Keep constantly wet; never let the rootzone dry out | Mildly toxic to pets |
| Equisetum japonicum | Direct sun (at least 4-6 hours) | Keep permanently wet or in shallow standing water | Mildly toxic to pets |
| Erman's Birch | Direct sun (at least 4-6 hours) | Regular watering for first 2–3 years; occasional once established | Pet-safe |
| Eryngium 'Jade Frost' | Direct sun (at least 4-6 hours) | Water while establishing, then only during prolonged drought | Mildly toxic to pets |
| Eryngium × zabelii 'Big Blue' | Direct sun (at least 4-6 hours) | Sparingly once established; water only in prolonged drought, roughly every 2-3 weeks | Mildly toxic to pets |
| Eryngium bourgatii 'Picos Blue' | Direct sun (at least 4-6 hours) | Minimal once established; only during extended dry spells, roughly every 2-3 weeks | Mildly toxic to pets |
| Eryngium giganteum 'Silver Ghost' | Direct sun (at least 4-6 hours) | Rarely once established; only in prolonged drought, roughly every 2-3 weeks | Mildly toxic to pets |
| Eryngium planum 'Blue Hobbit' | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water new plants until rooted | Mildly toxic to pets |
| Erythronium 'Pagoda' | Bright indirect light (just back from a sunny window) | Keep soil cool and evenly moist in spring; never let bulbs dry out completely | Mildly toxic to pets |
| Eschscholzia californica 'Thai Silk Rose Chiffon' | Direct sun (at least 4-6 hours) | When the soil is dry several centimetres down, roughly every 7-14 days | Mildly toxic to pets |
| Eternal Flame Plant | Bright indirect light (just back from a sunny window) | Roughly weekly in spring and summer; every 10-14 days in winter | Pet-safe |
| Etruscan honeysuckle | Direct sun (at least 4-6 hours) | Weekly during dry spells; established plants are drought-tolerant | Mildly toxic to pets |
| Eucryphia × nymansensis 'Nymansay' | Direct sun (at least 4-6 hours) | Keep the root zone consistently moist; water every 5-10 days in dry or hot weather, especially while establishing | Mildly toxic to pets |
| Euphorbia milii 'Lutea' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 1-2 weeks; less in winter | Toxic to pets |
| Euphorbia milii 'Rosea' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is fully dry, roughly every 10-14 days in growth | Toxic to pets |
| European Ash | Direct sun (at least 4-6 hours) | Moderate; deep watering during drought in first 3 years | Pet-safe |
| European Beech | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil starts to dry, frequently daily in summer | Mildly toxic to pets |
| European Columbine | Medium indirect light (a couple of metres from a window) | Water when the top 3 cm of soil dries, roughly weekly | Mildly toxic to pets |
| European feather grass | Direct sun (at least 4-6 hours) | Weekly in the first growing season; only during extreme drought thereafter | Pet-safe |
| European Hornbeam | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil begins to dry, often daily in summer | Mildly toxic to pets |
| European Larch | Direct sun (at least 4-6 hours) | When the surface just starts to dry, frequently twice daily in summer heat | Mildly toxic to pets |
| European Wild Ginger | Low light (north window or shaded room) | Moderate; water when the top 3–4 cm of soil dries out | Toxic to pets |
| Europeana Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly | Pet-safe |
| Everflame Hook Sedge | Direct sun (at least 4-6 hours) | Keep evenly moist; water weekly in dry weather and keep containers from drying out | Mildly toxic to pets |
| Evergreen Amaryllis | Bright indirect light (just back from a sunny window) | Year-round watering every 7–14 days; slightly reduced in winter but never fully withheld | Toxic to pets |
| Evergreen Candytuft | Direct sun (at least 4-6 hours) | Every 1–2 weeks when establishing; drought-tolerant once established | Mildly toxic to pets |
| evergreen miscanthus | Direct sun (at least 4-6 hours) | Every 7–14 days during the growing season; reduce but do not cease in mild winters | Pet-safe |
| Everlasting Sweet Pea | Direct sun (at least 4-6 hours) | Weekly while establishing; drought-tolerant once mature | Pet-safe |
| Eyelash Sage | Bright indirect light (just back from a sunny window) | Every 7-10 days once established | Pet-safe |
| Ezo Spruce | Direct sun (at least 4-6 hours) | When the top centimetre of soil starts to dry, often daily in summer | Mildly toxic to pets |
| Fagus sylvatica 'Dawyck' | Direct sun (at least 4-6 hours) | Weekly while establishing; water in dry spells | Toxic to pets |
| Fagus sylvatica 'Pendula' | Direct sun (at least 4-6 hours) | Weekly deep watering for the first 2-3 years, then rainfall-reliant | Mildly toxic to pets |
| Fagus sylvatica 'Purpurea' | Direct sun (at least 4-6 hours) | Weekly deep soak in the first 2-3 years, then rainfall-reliant | Mildly toxic to pets |
| Fairies' Thimbles | Bright indirect light (just back from a sunny window) | Weekly during active growth; less in winter | Pet-safe |
| Fairy Bells | Bright indirect light (just back from a sunny window) | Regular watering autumn to spring; completely dry in summer | Mildly toxic to pets |
| Fairy fan-flower | Direct sun (at least 4-6 hours) | Every 3–5 days in containers; every 7–10 days in-ground once established | Pet-safe |
| Fairy Flax | Direct sun (at least 4-6 hours) | Low — rainfall is generally sufficient; water only during severe summer drought | Mildly toxic to pets |
| Fairy Thimbles | Bright indirect light (just back from a sunny window) | Moderate — water regularly during the growing season | Mildly toxic to pets |
| Fallopia baldschuanica | Direct sun (at least 4-6 hours) | Water deeply during the first two growing seasons; established plants rarely need irrigation | Mildly toxic to pets |
| False Indigo Bush | Direct sun (at least 4-6 hours) | Regular watering (every 5–7 days) during establishment; drought-tolerant once established, or tolerates periodic inundation in wet sites | Mildly toxic to pets |
| False shamrock | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, every 5-7 days | Toxic to pets |
| False Solomon's Seal | Medium indirect light (a couple of metres from a window) | 2–3 times per week in the growing season; reduce in dormancy | Mildly toxic to pets |
| Falstaff Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season; more in heat or sandy soil | Pet-safe |
| Fama White scabiosa | Direct sun (at least 4-6 hours) | Every 7–10 days; less in winter | Pet-safe |
| Fanal astilbe | Medium indirect light (a couple of metres from a window) | 2–3 times per week in summer; weekly in cool or wet seasons | Pet-safe |
| Farewell-to-spring | Direct sun (at least 4-6 hours) | Every 7–10 days; reduce once established | Pet-safe |
| Farrer's Gentian | Bright indirect light (just back from a sunny window) | Keep consistently moist throughout the growing season | Mildly toxic to pets |
| Fastigiata Yew | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, about weekly while establishing | Toxic to pets |
| Fat Albert Blue Spruce | Direct sun (at least 4-6 hours) | Water deeply weekly for the first two to three years, then during prolonged dry spells | Mildly toxic to pets |
| Faulkner box | Bright indirect light (just back from a sunny window) | Weekly when young; every 10–14 days once established | Toxic to pets |
| feather grass | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; minimal in winter | Pet-safe |
| Featherleaf Rodgersia 'Superba' | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply 2-3 times per week in dry spells, more in summer heat | Mildly toxic to pets |
| feathertop grass | Direct sun (at least 4-6 hours) | Weekly when establishing; every 2 weeks once established | Pet-safe |
| Felicia Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly during the growing season, more often in hot weather | Pet-safe |
| Fennel-Leaved Sea Lavender | Direct sun (at least 4-6 hours) | Low to moderate — water to establish, then sparingly | Pet-safe |
| Fern-leaf Yarrow 'Gold Plate' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days; very infrequent once established | Toxic to pets |
| Ferner Osten Maiden Grass | Direct sun (at least 4-6 hours) | Weekly during the first season; established clumps tolerate drought and need water only in extended dry spells | Mildly toxic to pets |
| Fernleaf yarrow | Direct sun (at least 4-6 hours) | Water when top 5 cm of soil is dry; drought-tolerant once established | Mildly toxic to pets |
| Fetcani Pass Twinspur | Bright indirect light (just back from a sunny window) | Water when top 2–3 cm of soil dries out | Mildly toxic to pets |
| Few-flowered Abutilon | Bright indirect light (just back from a sunny window) | Every 7–10 days in active growth; fortnightly in cooler months | Pet-safe |
| Fiddle-leaf Pelargonium | Direct sun (at least 4-6 hours) | Water every 10-14 days in the growing season; reduce to monthly or less in winter | Toxic to pets |
| Fiebrig's Crown Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 7-10 days in spring and summer; every 4-6 weeks in autumn; minimal to none in winter | Pet-safe |
| Field Bindweed | Direct sun (at least 4-6 hours) | Low — extremely drought-tolerant once established | Toxic to pets |
| Field Chickweed | Direct sun (at least 4-6 hours) | Every 7–14 days in the growing season; very sparingly in autumn and winter | Pet-safe |
| Field Elm Bonsai | Direct sun (at least 4-6 hours) | When the top 2 cm of soil starts to dry, often daily in warm weather | Mildly toxic to pets |
| Field Gladiolus | Direct sun (at least 4-6 hours) | Moderate during late winter to late spring growing season; dry summer dormancy required | Toxic to pets |
| Field marigold | Direct sun (at least 4-6 hours) | Weekly during dry spells; self-sufficient once established | Pet-safe |
| Field Mouse-ear | Direct sun (at least 4-6 hours) | Very low — drought tolerant once established | Mildly toxic to pets |
| Field poppy | Direct sun (at least 4-6 hours) | Once established, every 10–14 days; keep seedbed moist until germination | Mildly toxic to pets |
| Field Sage | Direct sun (at least 4-6 hours) | Every 10-14 days once established; minimal in winter | Pet-safe |
| Field Scabious | Direct sun (at least 4-6 hours) | Water during establishment and dry spells, then occasionally | Mildly toxic to pets |
| Field Wood Rush | Direct sun (at least 4-6 hours) | No supplemental watering needed in typical temperate climates; relies on natural rainfall | Pet-safe |
| Fiesta Double Pink Impatiens | Medium indirect light (a couple of metres from a window) | Keep compost evenly moist at all times; water every 1-2 days in warm weather as double-flowered types are slightly more moisture-demanding than singles | Mildly toxic to pets |
| Filicoides Hinoki Cypress | Direct sun (at least 4-6 hours) | Every 5-7 days when young, then when the top few cm of soil dry | Mildly toxic to pets |
| Filifera Aurea Cypress | Direct sun (at least 4-6 hours) | Every 5-7 days while establishing, then when the top few cm of soil dry | Mildly toxic to pets |
| Finger Poppy Mallow | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; highly drought-tolerant | Mildly toxic to pets |
| Fire Alarm Heuchera | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, about weekly | Pet-safe |
| Fire and Ice Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Fire Barrel Cactus | Direct sun (at least 4-6 hours) | Every 2-4 weeks in summer; withhold in winter | Mildly toxic to pets |
| Fire Crown Cactus | Direct sun (at least 4-6 hours) | When the mix is completely dry, about every 10-14 days in growth; withhold entirely in winter | Pet-safe |
| Firefly heather | Direct sun (at least 4-6 hours) | Weekly during establishment; occasional deep watering once established | Pet-safe |
| Firethorn Bonsai | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil begins to dry, often daily in summer heat | Mildly toxic to pets |
| Fireworks Globe Amaranth | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Fishhook Barrel Cactus | Direct sun (at least 4-6 hours) | When the soil is completely dry, roughly every 2-3 weeks in summer; little to none from late autumn through winter | Pet-safe |
| Five-leaf akebia | Medium indirect light (a couple of metres from a window) | Once a week when establishing; drought-tolerant once mature | Mildly toxic to pets |
| Flaky Juniper | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; weekly during establishment year | Mildly toxic to pets |
| Flame Freesia | Direct sun (at least 4-6 hours) | Water freely in active growth; withhold completely during summer dormancy | Mildly toxic to pets |
| Flame nasturtium | Bright indirect light (just back from a sunny window) | Water regularly to maintain consistent moisture, especially in spring and summer | Pet-safe |
| Flamingo Feather Celosia | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 6-8 days | Pet-safe |
| Flamingo Flower | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix feels dry, roughly weekly in growth | Toxic to pets |
| Flamingo pieris | Bright indirect light (just back from a sunny window) | Weekly during dry weather | Toxic to pets |
| Flanagan's Sage | Direct sun (at least 4-6 hours) | Every 10-14 days during the growing season; rarely in winter | Pet-safe |
| Flat Sea Holly | Direct sun (at least 4-6 hours) | Low — water occasionally during the first growing season, then minimal | Pet-safe |
| Flax-leaved Tulip | Direct sun (at least 4-6 hours) | Water during active growth; keep dry in summer | Toxic to pets |
| Flesh-pink Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in growth; near-dry during dormancy | Mildly toxic to pets |
| Flexuose Nerine | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days during active growth | Toxic to pets |
| Floating Bur-reed | Direct sun (at least 4-6 hours) | Fully aquatic; floating or lightly rooted in 10–80 cm of water | Pet-safe |
| Florida Torreya | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, roughly every 10-14 days | Toxic to pets |
| Florist's Cyclamen | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil feels dry, roughly every 5-7 days | Toxic to pets |
| Florist's Gloxinia | Bright indirect light (just back from a sunny window) | Keep evenly moist during active growth; typically water once the top of the mix begins to dry, then taper off completely heading into dormancy. | Pet-safe |
| Flower Carpet Rose | Direct sun (at least 4-6 hours) | Deeply once a week in the growing season; more in containers or heat | Pet-safe |
| Flowering Cherry 'Kanzan' | Direct sun (at least 4-6 hours) | Water young trees weekly in dry spells; mature trees rarely need watering | Toxic to pets |
| Flowering coleus | Bright indirect light (just back from a sunny window) | Twice-weekly watering | Toxic to pets |
| Flowering currant | Bright indirect light (just back from a sunny window) | Weekly when establishing; drought-tolerant once mature | Mildly toxic to pets |
| Flowering Dogwood | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply weekly in dry spells | Mildly toxic to pets |
| Flowering Dogwood 'Cherokee Chief' | Bright indirect light (just back from a sunny window) | Weekly deep watering, more in drought | Pet-safe |
| Flowering maple | Direct sun (at least 4-6 hours) | When the top 1 cm (½ inch) of mix is dry, often every few days in summer | Mildly toxic to pets |
| Flowering Quince 'Crimson and Gold' | Direct sun (at least 4-6 hours) | Water while establishing; drought-tolerant once settled | Mildly toxic to pets |
| Flowering Quince 'Texas Scarlet' | Direct sun (at least 4-6 hours) | Weekly in the first year; rarely needed once established | Mildly toxic to pets |
| Flowering tobacco | Bright indirect light (just back from a sunny window) | Every 3–5 days; keep soil consistently moist | Toxic to pets |
| Fly Orchid | Bright indirect light (just back from a sunny window) | Seasonal; moist in spring, drier in summer dormancy | Mildly toxic to pets |
| Flying Saucer Cactus | Direct sun (at least 4-6 hours) | When the top of the soil is dry, roughly weekly to fortnightly in summer; keep nearly dry in winter | Pet-safe |
| Foamy Bells 'Sweet Tea' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Foothill Penstemon 'Margarita BOP' | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-21 days during the growing season | Mildly toxic to pets |
| Forbes' Glory of the Snow | Bright indirect light (just back from a sunny window) | Minimal once established; natural rainfall usually sufficient during growing season | Mildly toxic to pets |
| Forbes' Glory of the Snow | Bright indirect light (just back from a sunny window) | Relies on natural rainfall during its growing season; water lightly if spring is unusually dry | Toxic to pets |
| Forest Flame pieris | Bright indirect light (just back from a sunny window) | Weekly during dry periods | Toxic to pets |
| Forest Flame Pieris | Bright indirect light (just back from a sunny window) | Every 7-10 days in the growing season; established plants roughly every 10-14 days, more frequently during dry spells | Toxic to pets |
| Forest Lily Amaryllis | Medium indirect light (a couple of metres from a window) | Regular during growing season (every 7–10 days); significantly reduced or withheld during dormancy | Toxic to pets |
| Forget-me-not | Medium indirect light (a couple of metres from a window) | Weekly watering | Pet-safe |
| Forking larkspur | Direct sun (at least 4-6 hours) | Every 5–8 days | Toxic to pets |
| Formosa Lily | Direct sun (at least 4-6 hours) | 2-3 times per week in active growth | Toxic to pets |
| Formosanum Toad Lily | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water when the top of the soil begins to dry, often twice weekly in summer heat | Mildly toxic to pets |
| Forrest Fir | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry for young trees, roughly every 10-14 days during establishment | Mildly toxic to pets |
| Forrest's pieris | Bright indirect light (just back from a sunny window) | Regular; do not allow to dry out | Toxic to pets |
| Forsythia 'Lynwood Gold' | Direct sun (at least 4-6 hours) | Weekly while establishing, then only in extended dry spells | Pet-safe |
| Forsythia 'Show Off' | Direct sun (at least 4-6 hours) | Weekly to establish, then mainly during dry spells | Pet-safe |
| Forsythia Sage | Bright indirect light (just back from a sunny window) | Weekly during active growth | Pet-safe |
| Fortune Plum Yew | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, roughly every 10-14 days in the growing season | Toxic to pets |
| Fortune's Holly Fern | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Fortune's Plum Yew | Medium indirect light (a couple of metres from a window) | Every 7–14 days; allow the top inch of soil to partially dry between waterings | Toxic to pets |
| Fothergilla 'Mount Airy' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly weekly while establishing | Mildly toxic to pets |
| Fothergilla gardenii | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly weekly while establishing | Mildly toxic to pets |
| Fothergilla major | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about weekly while establishing | Mildly toxic to pets |
| Four-angled cassiope | Bright indirect light (just back from a sunny window) | Regularly during the growing season; keep consistently moist but never waterlogged | Pet-safe |
| Four-stamen Tamarisk | Direct sun (at least 4-6 hours) | Moderate to low; drought-tolerant once established | Pet-safe |
| Fourth of July Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season, more during heat | Pet-safe |
| Foxglove | Bright indirect light (just back from a sunny window) | Regularly — weekly in summer, less in winter | Toxic to pets |
| Foxglove 'Camelot Lavender' | Bright indirect light (just back from a sunny window) | Once or twice a week in dry conditions, ensuring even moisture during flower spike development | Toxic to pets |
| Foxglove 'Camelot' | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water weekly in dry weather | Toxic to pets |
| Foxglove beardtongue | Direct sun (at least 4-6 hours) | Every 7–10 days during establishment; drought-tolerant once established | Mildly toxic to pets |
| Foxglove Sage | Bright indirect light (just back from a sunny window) | Regular — keep soil evenly moist but not saturated | Mildly toxic to pets |
| Foxtail Orchid | Bright indirect light (just back from a sunny window) | When the bark approaches dryness, typically every 7-10 days | Pet-safe |
| Foxtail Pine | Direct sun (at least 4-6 hours) | Deep soak every 2-3 weeks once established; let soil dry between waterings | Mildly toxic to pets |
| Fragrant Bouquet Hosta | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water deeply 1-2 times weekly, more in heat | Toxic to pets |
| Fragrant Orchid | Direct sun (at least 4-6 hours) | Very low to low — rain-fed only | Mildly toxic to pets |
| Fragrant Solomon's Seal | Low light (north window or shaded room) | Every 5-7 days in active growth; drought-tolerant once established | Toxic to pets |
| Fragrant Sweet Box | Low light (north window or shaded room) | Every 10-14 days during establishment; established plants are very drought-tolerant and require watering only during prolonged dry periods | Mildly toxic to pets |
| Fragrant White Water Lily | Direct sun (at least 4-6 hours) | Permanently submerged aquatic — maintain water depth of 30–60 cm over the crown | Pet-safe |
| Francee Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Franchet Cotoneaster | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Franklin's Gem Boxwood | Direct sun (at least 4-6 hours) | Deep soak weekly during the first two seasons, then every 10-14 days in dry spells | Toxic to pets |
| Fraser Fir | Direct sun (at least 4-6 hours) | Regularly; moist but well-drained | Mildly toxic to pets |
| Frau Dagmar Hartopp Rose | Direct sun (at least 4-6 hours) | Weekly while establishing; drought-tolerant once settled | Pet-safe |
| Freesia | Direct sun (at least 4-6 hours) | Keep evenly moist while in growth; reduce to nothing once foliage yellows after flowering | Pet-safe |
| Freesia 'Pink Marble' | Direct sun (at least 4-6 hours) | Water regularly once shoots appear, roughly every 4-7 days, keeping soil moist but not wet | Pet-safe |
| Freesia 'Royal Blue' | Direct sun (at least 4-6 hours) | Water every 4-7 days during active growth, keeping the soil evenly moist but never waterlogged | Pet-safe |
| Freesia 'Yellow Passion' | Direct sun (at least 4-6 hours) | Water every 4-7 days while in growth, keeping soil moist but not soggy | Pet-safe |
| Freesia refracta | Direct sun (at least 4-6 hours) | Water every 5-7 days during winter-spring growth, keeping the soil just moist | Pet-safe |
| French marigold | Direct sun (at least 4-6 hours) | Once or twice weekly; let the top 2 cm of soil dry between waterings | Mildly toxic to pets |
| French Marigold 'Durango' | Direct sun (at least 4-6 hours) | When top 2-3 cm of soil is dry, every 3-6 days; containers more often | Mildly toxic to pets |
| French Tamarisk | Direct sun (at least 4-6 hours) | Moderate; drought-tolerant once established | Pet-safe |
| Fresh Look Red Cockscomb | Direct sun (at least 4-6 hours) | When the top 2–3 cm of soil is dry, roughly every 5–7 days | Pet-safe |
| Freyn's Pink | Direct sun (at least 4-6 hours) | Infrequent; drought-tolerant once established | Mildly toxic to pets |
| Fringed Bleeding Heart | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Toxic to pets |
| Fringed Cobra Lily | Medium indirect light (a couple of metres from a window) | Regularly during growing season; reduce in dormancy | Toxic to pets |
| Fringed Coreopsis | Direct sun (at least 4-6 hours) | Every 1–2 weeks once established; more frequently when young | Pet-safe |
| Fringed Houseleek | Direct sun (at least 4-6 hours) | Low — water sparingly, allowing soil to dry fully | Pet-safe |
| Fringed Loosestrife | Medium indirect light (a couple of metres from a window) | Regularly; keep soil consistently moist to wet | Mildly toxic to pets |
| Fringed Spurflower | Medium indirect light (a couple of metres from a window) | Regularly — keep soil evenly moist throughout the growing season | Mildly toxic to pets |
| Fringed-sepal Primulina | Medium indirect light (a couple of metres from a window) | Reduced in winter; moderate in spring and summer | Mildly toxic to pets |
| Fritillaria imperialis 'Lutea' | Direct sun (at least 4-6 hours) | Moderate moisture in spring growth; keep the dormant bulb dry in summer | Mildly toxic to pets |
| Fritillaria meleagris | Direct sun (at least 4-6 hours) | Keep soil moist through spring growth; tolerates damp ground | Mildly toxic to pets |
| Frohnleiten Epimedium | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry, roughly every 1-2 weeks | Mildly toxic to pets |
| Front Range Beardtongue | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; minimal in winter | Pet-safe |
| frost grass | Medium indirect light (a couple of metres from a window) | Weekly or whenever the top 2–3 cm of soil dries out; reduce in autumn and winter | Pet-safe |
| Frosted Curls Sedge | Bright indirect light (just back from a sunny window) | Weekly, or when top 2-3 cm of soil is dry | Pet-safe |
| Fuchsia | Bright indirect light (just back from a sunny window) | When the top 1-2 inches of soil feel dry (often every few days in summer) | Pet-safe |
| Fuchsia 'Alice Hoffman' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil or compost are dry, roughly every 7-10 days | Pet-safe |
| Fuchsia 'Annabel' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost are dry, roughly every 5-7 days in summer | Pet-safe |
| Fuchsia 'Beacon' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil or compost are dry, roughly every 7-10 days in summer | Pet-safe |
| Fuchsia 'Brutus' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil or compost are dry, roughly every 7-10 days | Pet-safe |
| Fuchsia 'Cardinal Farges' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil are dry, roughly every 8-12 days when established | Pet-safe |
| Fuchsia 'Celia Smedley' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost is dry, roughly every 3-5 days in summer | Mildly toxic to pets |
| Fuchsia 'Checkerboard' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost feels dry, roughly every 3-5 days in summer | Mildly toxic to pets |
| Fuchsia 'Dark Eyes' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost is dry, roughly every 2-4 days in summer baskets | Mildly toxic to pets |
| Fuchsia 'Dollar Princess' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost feels dry, roughly every 5-7 days in summer | Pet-safe |
| Fuchsia 'Gartenmeister Bonstedt' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 3-5 days in warm weather | Pet-safe |
| Fuchsia 'Golden Marinka' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost is dry, roughly every 5-7 days in summer | Pet-safe |
| Fuchsia 'Lady Thumb' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost is dry, roughly every 5-7 days in active growth | Pet-safe |
| Fuchsia 'Marinka' | Bright indirect light (just back from a sunny window) | When the top 2 cm of compost are dry, roughly every 5-7 days; daily checks in hot weather | Pet-safe |
| Fuchsia 'Mrs Popple' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil or compost is dry, roughly every 3-5 days during active growth | Pet-safe |
| Fuchsia 'Papoose' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost feels dry, roughly every 3-5 days in summer | Mildly toxic to pets |
| Fuchsia 'Phyllis' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost feels dry, roughly every 4-6 days in summer | Mildly toxic to pets |
| Fuchsia 'Pink Marshmallow' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost feel dry, roughly every 5-7 days; more frequently in summer heat | Pet-safe |
| Fuchsia 'Red Spider' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost are dry, roughly every 5-7 days in summer | Pet-safe |
| Fuchsia 'Snowcap' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost is dry, roughly every 3-5 days in the growing season | Mildly toxic to pets |
| Fuchsia 'Swingtime' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of compost is dry, roughly every 2-3 days in warm weather | Pet-safe |
| Fuchsia 'Thalia' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 3-5 days in warm weather | Pet-safe |
| Fuchsia 'Tom Thumb' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil or compost feels dry, roughly every 5-8 days | Pet-safe |
| Fuchsia 'Voodoo' | Bright indirect light (just back from a sunny window) | When the top 2 cm of compost are dry, roughly every 5-7 days in summer | Pet-safe |
| Fuchsia 'Winston Churchill' | Bright indirect light (just back from a sunny window) | When the top 2 cm of compost are dry, roughly every 6-8 days | Pet-safe |
| Fuchsia magellanica | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 3-5 days in summer heat | Pet-safe |
| Fujian Cypress | Bright indirect light (just back from a sunny window) | Once or twice a week during the growing season; reduce in winter | Mildly toxic to pets |
| Full Moon Maple | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly weekly in summer | Pet-safe |
| Furzey Darley Dale heath | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| Gaillardia 'Arizona Sun' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 7-10 days once established | Mildly toxic to pets |
| Gaillardia 'Burgundy' | Direct sun (at least 4-6 hours) | Once or twice a week during the first season; once every 2 weeks or less when established | Mildly toxic to pets |
| Gaillardia 'Dazzler' | Direct sun (at least 4-6 hours) | Once or twice a week in year one; once every 2 weeks or less once established | Mildly toxic to pets |
| Gaillardia 'Fanfare' | Direct sun (at least 4-6 hours) | Once a week during establishment; every 14 days or less once established in the ground | Mildly toxic to pets |
| Gaillardia 'Goblin' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days once established | Mildly toxic to pets |
| Gaillardia 'Mesa Red' | Direct sun (at least 4-6 hours) | Once or twice weekly during establishment; once every 14 days or less when established | Mildly toxic to pets |
| Gaillardia 'Mesa Yellow' | Direct sun (at least 4-6 hours) | Once or twice a week during establishment; every 14 days or less when established | Mildly toxic to pets |
| Gaillardia 'SpinTop Orange Halo' | Direct sun (at least 4-6 hours) | Once or twice a week during establishment; once every 10–14 days when established; check containers every 3–4 days in summer | Mildly toxic to pets |
| Gaillardia 'Sun Devil' | Direct sun (at least 4-6 hours) | Every 10-14 days once established; drought-tolerant | Mildly toxic to pets |
| Gaillardia 'Tizzy' | Direct sun (at least 4-6 hours) | Once a week during establishment; every 14 days or less when established in the ground; check every 3–5 days in containers | Mildly toxic to pets |
| Gaillardia 'Torchlight' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days in summer; reduce sharply in winter | Mildly toxic to pets |
| Garden Cape Primrose | Bright indirect light (just back from a sunny window) | Every 7-10 days in active growth; reduce to every 3-4 weeks in winter | Pet-safe |
| Garden Catmint | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; roughly every 7-10 days while establishing, then rarely | Mildly toxic to pets |
| Garden Gladiolus | Direct sun (at least 4-6 hours) | Weekly deep watering during active growth; reduce after flowering; cease after first frost kills foliage | Toxic to pets |
| Garden Phlox | Bright indirect light (just back from a sunny window) | 1-2 times per week during active growth | Mildly toxic to pets |
| Garden Phlox 'David' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 5-7 days | Pet-safe |
| Garden Phlox 'David' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Garden Pink 'Mrs Sinkins' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Garden verbena | Direct sun (at least 4-6 hours) | Every 3–5 days during active growth; reduce in cooler weather | Mildly toxic to pets |
| Gardenia | Bright indirect light (just back from a sunny window) | When the top 2-3cm of compost feels dry | Toxic to pets |
| Gardenia 'Frostproof' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the top 2-3 cm of soil dries, about every 4-7 days | Toxic to pets |
| Gardenia 'Kleim's Hardy' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the top 2-3 cm of soil begins to dry, roughly every 4-7 days | Toxic to pets |
| Gardenia 'Radicans' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 4-7 days | Toxic to pets |
| Gardenia 'Veitchii' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 4-7 days | Toxic to pets |
| Gaura 'Siskiyou Pink' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days during the growing season | Pet-safe |
| Gazania × hybrida 'Tiger Stripes' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Gazania rigens 'Daybreak Garden Sun' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Geisha Girl flowering quince | Bright indirect light (just back from a sunny window) | Weekly during establishment; occasional supplemental watering once established | Mildly toxic to pets |
| Geneva Bugle | Bright indirect light (just back from a sunny window) | Once weekly during establishment; every 10–14 days once established | Mildly toxic to pets |
| Gentian Sage | Direct sun (at least 4-6 hours) | Moderate; water when the top 2–3 cm of soil dries out | Pet-safe |
| Gentian Speedwell | Bright indirect light (just back from a sunny window) | Once a week in dry conditions; the plant tolerates moderate drought once established | Pet-safe |
| Gentle Hermione Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week during the growing season; more in heat | Pet-safe |
| Georgia Blue Speedwell | Direct sun (at least 4-6 hours) | Moderate; water when the top 2–3 cm of soil dries out | Pet-safe |
| Geranium 'Ann Folkard' | Direct sun (at least 4-6 hours) | Weekly while establishing and in dry spells; little once mature. | Mildly toxic to pets |
| Geranium 'Brookside' | Direct sun (at least 4-6 hours) | Weekly while establishing and in droughts; minimal once settled. | Mildly toxic to pets |
| Geranium 'Johnson's Blue' | Direct sun (at least 4-6 hours) | Water to establish in the first season; thereafter when the top few cm of soil is dry, roughly weekly in dry spells | Pet-safe |
| Geranium 'Nimbus' | Direct sun (at least 4-6 hours) | Weekly while establishing and during dry spells; drought-tolerant when mature | Mildly toxic to pets |
| Geranium 'Orion' | Direct sun (at least 4-6 hours) | Weekly while establishing and in dry spells; drought-tolerant once mature | Mildly toxic to pets |
| Geranium 'Patricia' | Direct sun (at least 4-6 hours) | Water when the top 3-4 cm dries, roughly weekly in growing season; established clumps tolerate some dryness | Mildly toxic to pets |
| Geranium (pelargonium) | Direct sun (at least 4-6 hours) | When the top of the soil is dry, every 5-10 days | Toxic to pets |
| Geranium × oxonianum 'Wargrave Pink' | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry; roughly weekly, more in heat | Mildly toxic to pets |
| Geranium cantabrigiense | Direct sun (at least 4-6 hours) | Weekly while establishing; very little once settled. | Mildly toxic to pets |
| Geranium cantabrigiense 'Biokovo' | Direct sun (at least 4-6 hours) | Weekly while establishing; very little thereafter. | Mildly toxic to pets |
| Geranium cantabrigiense 'Cambridge' | Bright indirect light (just back from a sunny window) | Water deeply during the first season; established plants need watering only in prolonged drought | Mildly toxic to pets |
| Geranium cinereum 'Ballerina' | Direct sun (at least 4-6 hours) | When the top few centimetres of soil are dry; sparingly once established | Mildly toxic to pets |
| Geranium cinereum 'Lawrence Flatman' | Direct sun (at least 4-6 hours) | When the top few centimetres are dry; keep on the dry side once established | Mildly toxic to pets |
| Geranium cinereum var. subcaulescens | Direct sun (at least 4-6 hours) | When the top few centimetres of soil are dry; sparingly once established | Mildly toxic to pets |
| Geranium clarkei 'Kashmir Purple' | Direct sun (at least 4-6 hours) | Weekly while establishing and in droughts; drought-tolerant once settled | Mildly toxic to pets |
| Geranium clarkei 'Kashmir White' | Direct sun (at least 4-6 hours) | Weekly while establishing and in droughts; drought-tolerant once settled | Mildly toxic to pets |
| Geranium endressii | Bright indirect light (just back from a sunny window) | Water through establishment; afterwards in dry spells only | Mildly toxic to pets |
| Geranium himalayense | Direct sun (at least 4-6 hours) | Weekly during the first season and in dry spells; established plants are drought-tolerant | Mildly toxic to pets |
| Geranium himalayense 'Gravetye' | Direct sun (at least 4-6 hours) | Weekly while establishing and during droughts; drought-tolerant once rooted | Mildly toxic to pets |
| Geranium himalayense 'Plenum' | Direct sun (at least 4-6 hours) | Weekly while establishing and in drought; otherwise drought-tolerant once settled | Mildly toxic to pets |
| Geranium macrorrhizum | Medium indirect light (a couple of metres from a window) | Water to establish; afterwards only in extended drought, roughly every 1-2 weeks if very dry | Pet-safe |
| Geranium macrorrhizum 'Bevan's Variety' | Medium indirect light (a couple of metres from a window) | When the top 4-5 cm of soil is dry; weekly to establish, seldom afterwards | Mildly toxic to pets |
| Geranium macrorrhizum 'Spessart' | Bright indirect light (just back from a sunny window) | Water deeply when top 5 cm of soil is dry; established plants need little to no supplemental water | Mildly toxic to pets |
| Geranium maculatum | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water deeply when the top 3-4 cm dries, roughly weekly in the growing season | Mildly toxic to pets |
| Geranium maculatum 'Elizabeth Ann' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply when the top 3-4 cm dries, about weekly during the growing season | Mildly toxic to pets |
| Geranium nodosum | Low light (north window or shaded room) | Water when the top 3-5 cm dries; established plants tolerate occasional dryness, roughly every 7-12 days in growing season | Mildly toxic to pets |
| Geranium phaeum | Medium indirect light (a couple of metres from a window) | Water when top 3-5 cm of soil is dry; keep evenly moist in its first season | Mildly toxic to pets |
| Geranium phaeum 'Album' | Medium indirect light (a couple of metres from a window) | Water when top 3-5 cm of soil is dry; keep evenly moist while establishing | Mildly toxic to pets |
| Geranium phaeum 'Lily Lovell' | Medium indirect light (a couple of metres from a window) | Water when top 3-5 cm of soil is dry; keep evenly moist while establishing | Mildly toxic to pets |
| Geranium phaeum 'Samobor' | Medium indirect light (a couple of metres from a window) | Water when top 3-5 cm of soil is dry; keep evenly moist while establishing | Mildly toxic to pets |
| Geranium pratense | Direct sun (at least 4-6 hours) | Roughly weekly in the first season and during prolonged dry spells; established plants need little. | Mildly toxic to pets |
| Geranium pratense 'Mrs Kendall Clark' | Direct sun (at least 4-6 hours) | About weekly while establishing and in dry spells; little once settled. | Mildly toxic to pets |
| Geranium pratense 'Plenum Violaceum' | Direct sun (at least 4-6 hours) | Weekly while establishing and during droughts; minimal once mature. | Mildly toxic to pets |
| Geranium pratense 'Victor Reiter Junior' | Direct sun (at least 4-6 hours) | Weekly while establishing and in dry spells; sparing once settled. | Mildly toxic to pets |
| Geranium psilostemon | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; about weekly, more in heat | Mildly toxic to pets |
| Geranium renardii | Direct sun (at least 4-6 hours) | Water when the top 4-5 cm dries; drought-tolerant once established, roughly every 10-14 days in growing season | Mildly toxic to pets |
| Geranium renardii 'Phillipe Vapelle' | Direct sun (at least 4-6 hours) | Water when the top 4-5 cm dries; drought-tolerant once established, roughly every 10-14 days in growing season | Mildly toxic to pets |
| Geranium sanguineum | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry; weekly while establishing, infrequently once mature | Mildly toxic to pets |
| Geranium sanguineum 'Album' | Direct sun (at least 4-6 hours) | Water when the top 3-5 cm of soil is dry; established plants are drought-tolerant | Mildly toxic to pets |
| Geranium sanguineum 'Max Frei' | Direct sun (at least 4-6 hours) | Water when top 3-5 cm of soil is dry; drought-tolerant once established | Mildly toxic to pets |
| Geranium sanguineum var. striatum | Direct sun (at least 4-6 hours) | Water when top 3-5 cm of soil is dry; drought-tolerant once established | Mildly toxic to pets |
| Geranium sylvaticum | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water deeply when the top 3-4 cm dries, roughly weekly in growing season | Mildly toxic to pets |
| Geranium sylvaticum 'Mayflower' | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water deeply when the top 3-4 cm dries, about weekly through the growing season | Mildly toxic to pets |
| Geranium wallichianum 'Buxton's Variety' | Bright indirect light (just back from a sunny window) | Water during establishment, then keep just-moist through summer; little needed in winter dormancy | Mildly toxic to pets |
| Geranium wallichianum 'Syabru' | Bright indirect light (just back from a sunny window) | Water during establishment, then keep evenly moist through the growing season | Mildly toxic to pets |
| Geranium x magnificum | Direct sun (at least 4-6 hours) | Weekly in the first season and during drought; established plants are fairly drought-tolerant | Mildly toxic to pets |
| Geranium x oxonianum | Bright indirect light (just back from a sunny window) | Water through the first season; thereafter only during sustained dry spells | Mildly toxic to pets |
| Geranium x oxonianum 'A.T. Johnson' | Bright indirect light (just back from a sunny window) | Water through establishment; thereafter only in prolonged dry spells | Mildly toxic to pets |
| Geranium x oxonianum 'Claridge Druce' | Bright indirect light (just back from a sunny window) | Water during the first season; afterwards only in extended drought | Mildly toxic to pets |
| Geranium x oxonianum 'Wargrave Pink' | Bright indirect light (just back from a sunny window) | Water during establishment; afterwards only in extended drought | Mildly toxic to pets |
| Gerbera Daisy | Bright indirect light (just back from a sunny window) | When the top 2-3 cm (1 in) of soil is dry, roughly 1-2 times per week in active growth | Pet-safe |
| German Empress Orchid Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm is dry, roughly every 7-10 days in growth | Pet-safe |
| Germander Speedwell | Medium indirect light (a couple of metres from a window) | Moderate — keep soil consistently moist, especially in summer | Pet-safe |
| Gertrude Jekyll Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season; more in heat or sandy soil | Pet-safe |
| Geum 'Mrs Bradshaw' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; keep evenly moist in summer | Mildly toxic to pets |
| Geum 'Mrs. J. Bradshaw' | Direct sun (at least 4-6 hours) | Water when the top 3 cm of soil dries, about weekly | Mildly toxic to pets |
| Geum 'Prinses Juliana' | Direct sun (at least 4-6 hours) | Keep soil moist but not waterlogged; water every 4-7 days in dry weather | Mildly toxic to pets |
| Geum 'Scarlet Tempest' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; keep evenly moist in summer | Mildly toxic to pets |
| Geum 'Totally Tangerine' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply every 5-7 days in dry spells | Mildly toxic to pets |
| Geum rivale 'Leonard's Variety' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days in dry spells, more in containers | Mildly toxic to pets |
| Giant Arrowhead | Direct sun (at least 4-6 hours) | Permanently aquatic — plant in still or slow-moving water 10–15 cm (4–6 in) deep; tolerates up to 30 cm (12 in). | Pet-safe |
| Giant Autumn Daffodil | Direct sun (at least 4-6 hours) | Minimal water during autumn–spring growth; bone dry in summer | Toxic to pets |
| Giant Bellflower | Medium indirect light (a couple of metres from a window) | Regularly — keep soil consistently moist throughout the growing season | Pet-safe |
| Giant Chincherinchee | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 10-14 days during active growth | Toxic to pets |
| Giant Chinese Silver Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; moderate, regular water thereafter | Mildly toxic to pets |
| Giant Dogwood | Bright indirect light (just back from a sunny window) | Weekly deep watering for young trees; deep watering in droughts for mature specimens | Pet-safe |
| Giant Feather Grass | Direct sun (at least 4-6 hours) | Every 7-10 days in the first season while establishing, then rarely | Mildly toxic to pets |
| Giant Montbretia | Direct sun (at least 4-6 hours) | Every 7-10 days in the growing season; reduce to occasional watering once foliage yellows in autumn | Mildly toxic to pets |
| Giant Pineapple Lily | Direct sun (at least 4-6 hours) | Regular during the growing season; minimal in winter dormancy | Toxic to pets |
| Giant Pineapple Lily | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry during active growth, roughly every 7-14 days | Toxic to pets |
| Giant Sacaton | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; more frequent during establishment | Pet-safe |
| Giant Sacaton Grass | Direct sun (at least 4-6 hours) | Water to establish the first season, then occasionally in drought, roughly every 2-3 weeks | Mildly toxic to pets |
| Giant Sea Holly | Direct sun (at least 4-6 hours) | Moderate — water regularly to keep soil evenly moist, especially in summer | Pet-safe |
| Giant Sequoia | Direct sun (at least 4-6 hours) | Weekly while establishing; deep occasional soaks once mature | Mildly toxic to pets |
| Giant Sequoia 'Blauer Eichzwerg' | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry; keep evenly moist, every 7-10 days | Mildly toxic to pets |
| Giant Sequoia 'Glaucum' | Direct sun (at least 4-6 hours) | Deeply once or twice a week while establishing; then during dry spells | Mildly toxic to pets |
| Giant Snowdrop | Bright indirect light (just back from a sunny window) | Regular moisture during growth; tolerates drier summer dormancy than G. nivalis | Toxic to pets |
| Giant Snowflake Bacopa | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of potting mix feels dry, roughly every 3-5 days in warm weather | Pet-safe |
| Giant Spider Lily | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days in the growing season | Toxic to pets |
| Giant Sunburst Lotus | Direct sun (at least 4-6 hours) | Aquatic — continuously in still or gently moving water | Mildly toxic to pets |
| Giant Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist spring through early summer; tolerates drier conditions once fully summer-dormant. | Mildly toxic to pets |
| Ginkgo 'Autumn Gold' | Direct sun (at least 4-6 hours) | Regularly for the first 2-3 years; drought-tolerant once established | Mildly toxic to pets |
| Ginkgo 'Fastigiata' | Direct sun (at least 4-6 hours) | Weekly while establishing in the first 1-2 years; rarely once mature | Mildly toxic to pets |
| Ginkgo 'Mariken' | Direct sun (at least 4-6 hours) | Weekly when young or container-grown; occasionally once established in ground | Mildly toxic to pets |
| Ginkgo 'Saratoga' | Direct sun (at least 4-6 hours) | Weekly during establishment; minimal once mature | Mildly toxic to pets |
| Girard's Thrift | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season; very sparingly in winter | Mildly toxic to pets |
| Glacier Pink | Direct sun (at least 4-6 hours) | Low; water very sparingly, letting the soil nearly dry out between waterings | Mildly toxic to pets |
| Gladiolus 'Espresso' | Direct sun (at least 4-6 hours) | Keep evenly moist during growth, roughly 25 mm per week and more during spike formation | Toxic to pets |
| Gladiolus 'Impressive' | Direct sun (at least 4-6 hours) | Keep evenly moist during growth, roughly 25 mm per week in dry spells | Toxic to pets |
| Gladiolus 'Purple Flora' | Direct sun (at least 4-6 hours) | Keep evenly moist in growth, about 25 mm per week, more in heat and as spikes form | Toxic to pets |
| Gladiolus 'Traderhorn' | Direct sun (at least 4-6 hours) | Roughly weekly, 25mm (1 inch) per week during active growth and budding | Toxic to pets |
| Gladiolus callianthus | Direct sun (at least 4-6 hours) | Weekly during growth, keeping soil moist but never sodden | Toxic to pets |
| Glandular Heron's Bill | Direct sun (at least 4-6 hours) | Water sparingly; allow soil to dry almost completely between waterings | Mildly toxic to pets |
| Glaucous Lampranthus | Direct sun (at least 4-6 hours) | Every 2–3 weeks in summer growing season; every 4–6 weeks in winter | Mildly toxic to pets |
| Glaucous Sedge | Medium indirect light (a couple of metres from a window) | Low to moderate — drought-tolerant when established | Pet-safe |
| Glaziou's Fuchsia | Bright indirect light (just back from a sunny window) | Water freely in growth; reduce in winter | Pet-safe |
| Gleditsia triacanthos 'Sunburst' | Direct sun (at least 4-6 hours) | Water weekly for the first two seasons; established trees are notably drought-tolerant | Pet-safe |
| Gleditsia triacanthos f. inermis | Direct sun (at least 4-6 hours) | Water weekly for the first two seasons; established trees are highly drought-tolerant | Pet-safe |
| Globe amaranth | Direct sun (at least 4-6 hours) | Every 7–10 days; drought-tolerant once established | Pet-safe |
| Globe candytuft | Direct sun (at least 4-6 hours) | Every 7–10 days; keep evenly moist but not waterlogged | Pet-safe |
| Gloriosa Daisy | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry out; about weekly, more in heat | Mildly toxic to pets |
| Glory of Texas Cactus | Direct sun (at least 4-6 hours) | When the soil is completely dry, roughly every 10-14 days in summer and once every 5-6 weeks in winter | Pet-safe |
| Glory of the Snow | Bright indirect light (just back from a sunny window) | Low; relies on natural rainfall in most temperate gardens | Mildly toxic to pets |
| Glory of the Sun | Direct sun (at least 4-6 hours) | Moderate in growth; completely dry in summer dormancy | Mildly toxic to pets |
| Glossy Abelia | Direct sun (at least 4-6 hours) | Regularly during the first growing season; occasional deep watering once established | Pet-safe |
| Gloxinia perennis | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Pet-safe |
| Gloxinia sylvatica | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Pet-safe |
| Glyceria maxima 'Variegata' | Direct sun (at least 4-6 hours) | Keep constantly moist to shallowly submerged | Toxic to pets |
| Gmelin's Sea Lavender | Direct sun (at least 4-6 hours) | Every 2–3 weeks when established | Pet-safe |
| Gnome Spruce | Direct sun (at least 4-6 hours) | Every 5-7 days; water when the surface of the small root zone dries | Pet-safe |
| Goat's Horn Cactus | Direct sun (at least 4-6 hours) | When the soil is fully dry, roughly every 2-3 weeks in summer; keep dry from late autumn through winter | Pet-safe |
| Goat's-beard | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Mildly toxic to pets |
| Gold Charm Holiday Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Pet-safe |
| Gold Coast Juniper | Direct sun (at least 4-6 hours) | Water deeply through the first season; thereafter mainly in prolonged drought | Toxic to pets |
| Gold Dew Tufted Hair Grass | Bright indirect light (just back from a sunny window) | Moderate to frequent — prefers consistently moist soil | Pet-safe |
| Gold Dust Alyssum | Direct sun (at least 4-6 hours) | Fortnightly to monthly once established (very drought-tolerant) | Pet-safe |
| Gold Haze heather | Direct sun (at least 4-6 hours) | Weekly during first season; occasional watering once established | Pet-safe |
| Gold Heart Bleeding Heart | Medium indirect light (a couple of metres from a window) | Weekly during the growing season, reducing as foliage dies back in summer | Toxic to pets |
| Gold Mound Spirea | Direct sun (at least 4-6 hours) | Weekly when establishing; every 1–2 weeks once established | Pet-safe |
| Gold Plate yarrow | Direct sun (at least 4-6 hours) | Every 1–2 weeks once established; more frequent during establishment | Mildly toxic to pets |
| Gold Rush Dawn Redwood | Direct sun (at least 4-6 hours) | Regularly — keep soil consistently moist, especially in summer | Pet-safe |
| Gold Rush Dawn Redwood | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days in summer | Mildly toxic to pets |
| Golden Alexanders | Bright indirect light (just back from a sunny window) | Weekly or as needed to keep soil moist | Pet-safe |
| Golden Angel's Trumpet | Direct sun (at least 4-6 hours) | Every 2–4 days in summer (soil evenly moist; never waterlogged) | Toxic to pets |
| Golden Ash | Direct sun (at least 4-6 hours) | Moderate; regular deep watering when establishing | Pet-safe |
| Golden Ball Cactus | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 7-10 days in summer; minimal in winter | Pet-safe |
| Golden Bow Dendrobium | Bright indirect light (just back from a sunny window) | Plentiful in warm summer growth; markedly reduced and near-dry over a cool winter rest | Pet-safe |
| Golden Cinquefoil | Direct sun (at least 4-6 hours) | Every 10–14 days; drought-tolerant once established | Pet-safe |
| Golden Club | Direct sun (at least 4-6 hours) | Permanently aquatic; plant crown 10–15 cm (4–6 in) below the water surface | Mildly toxic to pets |
| Golden Columbine | Bright indirect light (just back from a sunny window) | Once or twice a week during active growth; drought-tolerant once established | Toxic to pets |
| Golden Creeping Jenny | Bright indirect light (just back from a sunny window) | Every 3–7 days; keep consistently moist; will tolerate standing water as a pond marginal | Mildly toxic to pets |
| Golden Crocus | Direct sun (at least 4-6 hours) | Minimal supplemental water needed; relies on natural rainfall; ensure summer-dry conditions for corm dormancy | Mildly toxic to pets |
| Golden Deodar Cedar | Direct sun (at least 4-6 hours) | Moderately; regularly during establishment, infrequently once mature | Mildly toxic to pets |
| Golden Deodar Cedar | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-14 days in the growing season | Mildly toxic to pets |
| Golden everlasting | Direct sun (at least 4-6 hours) | Every 7–10 days once established; reduce in autumn | Pet-safe |
| golden fescue | Direct sun (at least 4-6 hours) | Low; water every 10–14 days during the growing season, less in winter | Pet-safe |
| Golden Globe Arborvitae | Direct sun (at least 4-6 hours) | Twice weekly while establishing; weekly thereafter | Mildly toxic to pets |
| Golden Goddess Bamboo | Direct sun (at least 4-6 hours) | Twice weekly during dry periods in summer; reduce to weekly or less in cooler seasons | Pet-safe |
| Golden Ice Plant | Direct sun (at least 4-6 hours) | Every 2–3 weeks (allow soil to dry completely between waterings) | Pet-safe |
| Golden Rat Tail Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in summer and every 3-4 weeks in winter | Pet-safe |
| Golden Sea Lavender | Direct sun (at least 4-6 hours) | Every 2–4 weeks when established; very little in winter | Pet-safe |
| Golden St. John's Wort | Direct sun (at least 4-6 hours) | Weekly during the first growing season; minimal once established | Mildly toxic to pets |
| Golden Torch Cactus | Direct sun (at least 4-6 hours) | When the soil is dry, about weekly to fortnightly in summer; keep dry in winter | Pet-safe |
| Golden-Edged Cymbidium | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, about every 5-7 days, drier in winter | Pet-safe |
| Golden-Leaved Jerusalem Sage | Direct sun (at least 4-6 hours) | Low — water every 2–3 weeks in summer; keep dry in winter | Mildly toxic to pets |
| Golden-rayed Lily | Direct sun (at least 4-6 hours) | When top 3 cm of soil is dry | Toxic to pets |
| Goldencup St. John's Wort | Bright indirect light (just back from a sunny window) | Once or twice weekly when young; every 1–2 weeks once established | Mildly toxic to pets |
| Goldenrod | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Mildly toxic to pets |
| Goldfish Plant | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 7-10 days in growth | Pet-safe |
| Goldmoss Stonecrop | Direct sun (at least 4-6 hours) | Rarely — established plants rely on rainfall; water only in prolonged drought | Mildly toxic to pets |
| Goldtau Hair Grass | Medium indirect light (a couple of metres from a window) | Every 5-10 days; keep consistently moist | Pet-safe |
| Goldtau Tufted Hair Grass | Bright indirect light (just back from a sunny window) | Keep evenly moist, watering deeply 1-2 times weekly when dry | Mildly toxic to pets |
| Gomphrena globosa 'QIS Pink' | Direct sun (at least 4-6 hours) | Water deeply once a week; let soil dry between waterings | Pet-safe |
| Gomphrena haageana 'Strawberry Fields' | Direct sun (at least 4-6 hours) | Water deeply about weekly; allow soil to dry between | Mildly toxic to pets |
| Good Luck Plant | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days during active growth | Mildly toxic to pets |
| Gooseneck Loosestrife | Medium indirect light (a couple of metres from a window) | Regularly; moist soil preferred | Mildly toxic to pets |
| Gowen Cypress | Direct sun (at least 4-6 hours) | Infrequently; drought-tolerant once established | Mildly toxic to pets |
| Graceful Cattail | Direct sun (at least 4-6 hours) | Continuously moist to submerged | Pet-safe |
| Gracillimus Maiden Grass | Direct sun (at least 4-6 hours) | Weekly in year one, then mainly during extended dry spells | Mildly toxic to pets |
| Graham Thomas Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Grand Cape Primrose | Bright indirect light (just back from a sunny window) | Every 7-14 days in growth; monthly in winter | Pet-safe |
| Grand Fir | Direct sun (at least 4-6 hours) | Weekly during establishment; rainfall-dependent once mature | Pet-safe |
| Grape-leaved Anemone 'Robustissima' | Bright indirect light (just back from a sunny window) | When the top 4-5 cm of soil is dry, roughly every 7-14 days | Toxic to pets |
| Grapeleaf Abutilon | Direct sun (at least 4-6 hours) | Moderate; established plants are fairly drought-tolerant | Mildly toxic to pets |
| Grass-Leaved Edraianthus | Direct sun (at least 4-6 hours) | Low — allow soil to partially dry between waterings | Mildly toxic to pets |
| Grassy Arrowhead | Direct sun (at least 4-6 hours) | Permanently aquatic; grow in standing water 5–30 cm (2–12 in) deep | Pet-safe |
| Gray Birch | Direct sun (at least 4-6 hours) | Moderate; tolerates drier conditions than most birches once established | Pet-safe |
| Gray Goldenrod | Direct sun (at least 4-6 hours) | Very drought-tolerant; supplemental water rarely needed | Pet-safe |
| Gray's sedge | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water every 2–4 days in dry weather | Pet-safe |
| Grayleaf Cranesbill | Direct sun (at least 4-6 hours) | Every 7–10 days when dry; very sparingly in winter | Pet-safe |
| Grayswood Pink Rock Rose | Direct sun (at least 4-6 hours) | Minimal once established — established plants are drought-tolerant and need watering only during prolonged summer dry spells. | Mildly toxic to pets |
| Great Expectations Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Great Masterwort | Medium indirect light (a couple of metres from a window) | Regularly — keep soil evenly moist throughout the growing season | Mildly toxic to pets |
| Great Mullein | Direct sun (at least 4-6 hours) | Low — once established, rainfall is usually sufficient | Mildly toxic to pets |
| Great Pond Sedge | Direct sun (at least 4-6 hours) | Permanently wet; grows in standing water or waterlogged soil | Pet-safe |
| Great Solomon's Seal | Low light (north window or shaded room) | Every 4-6 days in active growth; drought-tolerant once established | Toxic to pets |
| Great White Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist in spring; reduce after summer dormancy | Mildly toxic to pets |
| Great Wood Rush | Medium indirect light (a couple of metres from a window) | Low to moderate; established plants rarely need supplemental watering in temperate climates | Pet-safe |
| Greater Coreopsis | Bright indirect light (just back from a sunny window) | Low to moderate; drought-tolerant once established | Pet-safe |
| Greater Duckweed | Direct sun (at least 4-6 hours) | Permanently floating on water surface | Pet-safe |
| Greater Fringed Gentian | Bright indirect light (just back from a sunny window) | Regular — consistently moist | Pet-safe |
| Greater Knapweed | Direct sun (at least 4-6 hours) | Rarely needed once established; water new plants occasionally through their first summer | Pet-safe |
| Greater Periwinkle | Medium indirect light (a couple of metres from a window) | Every 5–7 days during active growth; every 10–14 days once established | Toxic to pets |
| Greater Pyramidal Saxifrage | Direct sun (at least 4-6 hours) | Every 10–14 days during the growing season; very sparingly in winter | Pet-safe |
| Greater Quaking Grass | Direct sun (at least 4-6 hours) | Water seedlings until established, then only during prolonged drought, roughly every 10-14 days | Mildly toxic to pets |
| Greater Sea Kale | Bright indirect light (just back from a sunny window) | Moderate — water regularly while establishing, then during dry spells | Mildly toxic to pets |
| Greater Sea Spurrey | Direct sun (at least 4-6 hours) | Minimal supplemental watering; relies on coastal rainfall and tidal humidity | Mildly toxic to pets |
| Greater Spearwort | Direct sun (at least 4-6 hours) | Shallow to moderate water depth: 10–45 cm | Toxic to pets |
| Greater Stitchwort | Medium indirect light (a couple of metres from a window) | Moderate; keep soil evenly moist during spring and summer | Mildly toxic to pets |
| Greater Woodrush | Low light (north window or shaded room) | Weekly in first season, then largely self-sufficient | Pet-safe |
| Grecian Windflower | Bright indirect light (just back from a sunny window) | Moderate in spring, dry during summer dormancy | Toxic to pets |
| Greek Cyclamen | Bright indirect light (just back from a sunny window) | Dry in summer dormancy; moderate during autumn and winter growth | Toxic to pets |
| Greek Fir | Direct sun (at least 4-6 hours) | Every 2–3 weeks during establishment; rarely needed once mature | Pet-safe |
| Greek Jancaea | Medium indirect light (a couple of metres from a window) | Little and often to keep root zone moist; almost dry during winter dormancy | Pet-safe |
| Greek yarrow | Direct sun (at least 4-6 hours) | Every 10–14 days during establishment; minimal once mature | Mildly toxic to pets |
| Green Arrow Arum | Direct sun (at least 4-6 hours) | Permanent standing water or consistently saturated soil; never allow to dry out | Toxic to pets |
| Green Ash | Direct sun (at least 4-6 hours) | Weekly when establishing; drought-tolerant once mature | Pet-safe |
| Green Comet Milkweed | Bright indirect light (just back from a sunny window) | Low; highly drought-tolerant once established | Toxic to pets |
| Green Dragon | Medium indirect light (a couple of metres from a window) | Regularly during spring and summer growing season | Toxic to pets |
| Green Gem Boxwood | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, about weekly while establishing | Toxic to pets |
| Green Ixia | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days during active growth | Mildly toxic to pets |
| Green Milkweed | Direct sun (at least 4-6 hours) | Low to moderate; every 1–2 weeks once established | Toxic to pets |
| Green Moor Grass | Medium indirect light (a couple of metres from a window) | Every 1–2 weeks during establishment; largely self-sufficient once established | Pet-safe |
| Green Sheen Japanese Spurge | Low light (north window or shaded room) | Weekly during the first two growing seasons; once established, water during prolonged dry spells only | Mildly toxic to pets |
| Green Snowdrop | Bright indirect light (just back from a sunny window) | Relies on natural rainfall during the growing season; keep moist during autumn planting and winter–spring growth | Toxic to pets |
| Green Velvet Boxwood | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, about weekly while establishing | Toxic to pets |
| Green-Flowered Galtonia | Direct sun (at least 4-6 hours) | Regular from spring through late summer; reduce in autumn | Pet-safe |
| Green-winged Orchid | Direct sun (at least 4-6 hours) | Rain-fed; moist spring, dry summer dormancy | Mildly toxic to pets |
| Greenspire Linden | Direct sun (at least 4-6 hours) | Moderate; deep watering during establishment and drought | Pet-safe |
| Greenstem Forsythia | Direct sun (at least 4-6 hours) | Weekly while establishing, then drought-tolerant | Pet-safe |
| Grefsheim Spirea | Direct sun (at least 4-6 hours) | Weekly until established; reduce to occasional watering in drought | Pet-safe |
| Greig's Tulip | Direct sun (at least 4-6 hours) | Rainfall-dependent during growth; needs dry summer dormancy | Toxic to pets |
| Grey Club-rush | Direct sun (at least 4-6 hours) | Shallow to moderately deep aquatic; 10–60 cm over the crown | Pet-safe |
| Grey Goldenrod | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Pet-safe |
| Grey Moor Grass | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Pet-safe |
| Grey Sage | Direct sun (at least 4-6 hours) | Every 10-14 days; drought-tolerant once established | Pet-safe |
| Grey sedge | Medium indirect light (a couple of metres from a window) | Occasional once established; more frequent in full sun or sandy soil | Pet-safe |
| Grey Speedwell | Direct sun (at least 4-6 hours) | Every 14–21 days during growing season; barely any in winter | Pet-safe |
| Grey-Headed Coneflower | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; drought-tolerant | Pet-safe |
| Guatemalan Blue Sage | Medium indirect light (a couple of metres from a window) | Every 5-7 days during the growing season | Pet-safe |
| guelder rose | Bright indirect light (just back from a sunny window) | Weekly when young; every 1–2 weeks once established | Mildly toxic to pets |
| Guernsey Lily | Direct sun (at least 4-6 hours) | Completely dry in summer; begin watering in late summer as flower spikes emerge; water regularly until foliage dies back in late spring | Toxic to pets |
| Gulf Muhly | Direct sun (at least 4-6 hours) | Water through the first season to establish, then only in drought, roughly every 2 weeks | Mildly toxic to pets |
| Gunnera manicata | Bright indirect light (just back from a sunny window) | Keep permanently wet; never let the rootzone dry | Mildly toxic to pets |
| Gymnocarpium dryopteris 'Plumosum' | Low light (north window or shaded room) | Keep the soil consistently moist, watering when the top 1-2 cm dries, roughly every 4-6 days | Mildly toxic to pets |
| H.E. Beale heather | Direct sun (at least 4-6 hours) | Weekly during first season; monthly or as needed once established | Pet-safe |
| Hackberry Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil dries, regularly in summer | Mildly toxic to pets |
| Hair sedge | Bright indirect light (just back from a sunny window) | Regular watering to maintain even moisture; reduce slightly in winter | Pet-safe |
| Hairy Abutilon | Bright indirect light (just back from a sunny window) | Regularly; keep soil evenly moist in growth | Mildly toxic to pets |
| Hairy Alpine Primrose | Bright indirect light (just back from a sunny window) | Every 5–7 days during active growth; minimal in summer and winter | Mildly toxic to pets |
| Hairy alumroot | Medium indirect light (a couple of metres from a window) | Once or twice per week during active growth; less in winter | Pet-safe |
| Hairy Beardtongue | Bright indirect light (just back from a sunny window) | Every 1–2 weeks once established; more frequent when newly planted | Pet-safe |
| Hairy Coreopsis | Direct sun (at least 4-6 hours) | Low to moderate; water during establishment, then as needed during drought | Pet-safe |
| Hairy Hydrangea | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil feels dry, roughly every 5-7 days in summer | Toxic to pets |
| Hairy Primrose | Bright indirect light (just back from a sunny window) | Regularly during active growth (spring–autumn); sparingly in winter | Toxic to pets |
| Hairy Rattleweed | Direct sun (at least 4-6 hours) | Low; allow soil to dry between waterings | Toxic to pets |
| Hairy Rock Jasmine | Direct sun (at least 4-6 hours) | Sparingly; dry conditions preferred especially in winter | Pet-safe |
| Hairy Rock-cress | Direct sun (at least 4-6 hours) | Low; water only during prolonged drought | Mildly toxic to pets |
| Hairy Sage | Direct sun (at least 4-6 hours) | Moderate; water when the top 3–5 cm of soil is dry | Mildly toxic to pets |
| Hairy Sinningia | Bright indirect light (just back from a sunny window) | Weekly during growth; withheld during dormancy | Pet-safe |
| Hairy Solomon's Seal | Medium indirect light (a couple of metres from a window) | Regular; keep evenly moist | Mildly toxic to pets |
| Hairy St John's-wort | Medium indirect light (a couple of metres from a window) | Moderate — water when the top 2–3 cm of soil is dry | Toxic to pets |
| Hairy Sun Rose | Direct sun (at least 4-6 hours) | Very low — once every 3–4 weeks in the growing season once established | Mildly toxic to pets |
| Hairy Thrift | Direct sun (at least 4-6 hours) | Every 2–3 weeks when established | Mildly toxic to pets |
| Hairy Violet | Medium indirect light (a couple of metres from a window) | Water moderately; allow the top centimetre of soil to dry between waterings. | Pet-safe |
| Hairy Woodrush | Low light (north window or shaded room) | Every 7–10 days during the growing season | Pet-safe |
| Hairy-fruited Draba | Direct sun (at least 4-6 hours) | Every 10–14 days during growth; very little in winter | Pet-safe |
| Hakonechloa All Gold | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water 1-2 times weekly, more in heat | Mildly toxic to pets |
| Halesia carolina | Bright indirect light (just back from a sunny window) | Weekly while establishing; regular watering in dry spells | Pet-safe |
| Halesia monticola | Bright indirect light (just back from a sunny window) | Weekly while establishing; regular watering in dry spells | Pet-safe |
| Half-Stained Sage | Direct sun (at least 4-6 hours) | Every 7–10 days in active growth; reduce in winter | Mildly toxic to pets |
| Hall Totara | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 10-14 days for young plants | Toxic to pets |
| Hameln Dwarf Fountain Grass | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry, about weekly while establishing; drought-tolerant once settled | Pet-safe |
| Hameln Fountain Grass | Direct sun (at least 4-6 hours) | Weekly for the first season; every 2 weeks once established | Pet-safe |
| Hansa Rose | Direct sun (at least 4-6 hours) | Water weekly while establishing; drought-tolerant once settled | Pet-safe |
| Happy Wanderer | Bright indirect light (just back from a sunny window) | Low to moderate; drought tolerant once established | Mildly toxic to pets |
| Hard Rush | Direct sun (at least 4-6 hours) | Consistently moist to saturated soil; tolerates standing water to 7 cm (3 in) deep | Pet-safe |
| Hardy Cyclamen | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry during active growth (autumn-spring); withhold water during summer dormancy | Toxic to pets |
| Hardy Geranium 'Rozanne' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; about weekly, more in heat or containers | Mildly toxic to pets |
| Hardy Ice Plant | Direct sun (at least 4-6 hours) | Every 2–3 weeks during active growth; keep dry in winter | Mildly toxic to pets |
| Hardy Ice Plant | Direct sun (at least 4-6 hours) | When the top 3–4 cm of soil is dry, roughly every 7–14 days in summer and very sparingly in winter | Mildly toxic to pets |
| Hare's Tail Grass | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-14 days | Pet-safe |
| Harebell | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Pet-safe |
| Harlequin Flower | Direct sun (at least 4-6 hours) | Water freely when in active growth; stop completely once foliage yellows | Mildly toxic to pets |
| Harlow Carr Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in growth; more in heat or pots | Pet-safe |
| Hatfieldii Yew | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, about weekly while establishing | Toxic to pets |
| Hatschbach's Fuchsia | Bright indirect light (just back from a sunny window) | Water freely in growth; keep just moist in winter | Pet-safe |
| Hawaii Blue Flossflower | Direct sun (at least 4-6 hours) | When the top 2 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Haworth's Lampranthus | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season; sparingly in summer dormancy | Mildly toxic to pets |
| Haygarth's Cape Primrose | Bright indirect light (just back from a sunny window) | Every 7-10 days in growth; every 3-4 weeks in winter | Pet-safe |
| Hazel Smith Sequoia | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-14 days in the growing season | Mildly toxic to pets |
| Heart-leaved Globe Daisy | Direct sun (at least 4-6 hours) | Every 2–3 weeks in summer; very sparingly in winter | Pet-safe |
| Heartleaf Bergenia | Medium indirect light (a couple of metres from a window) | Every 7–10 days in the growing season; reduce significantly in winter | Pet-safe |
| Heartleaf Foamflower | Medium indirect light (a couple of metres from a window) | Regular; keep consistently moist | Pet-safe |
| Heartleaf Golden Alexanders | Bright indirect light (just back from a sunny window) | Every 1–2 weeks once established; more frequently in the first season | Pet-safe |
| Heartleaf Hornbeam | Medium indirect light (a couple of metres from a window) | Moderate; water regularly when young; maintain consistent moisture | Pet-safe |
| Heath Speedwell | Bright indirect light (just back from a sunny window) | Low to moderate — allow soil to partially dry between waterings | Pet-safe |
| Heath Spotted Orchid | Bright indirect light (just back from a sunny window) | Consistent moisture from rainfall | Mildly toxic to pets |
| Heath-leaved Sage | Direct sun (at least 4-6 hours) | Low; water deeply every 2–3 weeks when established | Mildly toxic to pets |
| Heather | Direct sun (at least 4-6 hours) | Weekly during establishment; drought-tolerant once established | Pet-safe |
| Heavenly blue morning glory | Direct sun (at least 4-6 hours) | Once or twice a week in dry periods; reduce once established | Toxic to pets |
| Heavy Metal Switch Grass | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water deeply every 1-2 weeks while young | Mildly toxic to pets |
| Heavy Metal Switchgrass | Direct sun (at least 4-6 hours) | Weekly when establishing; every 2–3 weeks once established | Pet-safe |
| Hedera colchica | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in growth | Toxic to pets |
| Hedera colchica 'Dentata Variegata' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in growth | Toxic to pets |
| Hedge Bedstraw | Bright indirect light (just back from a sunny window) | Low to moderate — rainfall usually sufficient | Mildly toxic to pets |
| Hedge bindweed | Direct sun (at least 4-6 hours) | Tolerates drought once established; water young plants weekly until roots are established | Mildly toxic to pets |
| Hedge Woundwort | Medium indirect light (a couple of metres from a window) | Regularly during active growth; reduce in winter | Mildly toxic to pets |
| Hedgehog Cactus | Bright indirect light (just back from a sunny window) | When the soil is dry, roughly every 1-2 weeks in summer; keep dry in winter | Pet-safe |
| Hedgerow Cranesbill | Bright indirect light (just back from a sunny window) | Low to moderate; water only to establish, then drought-tolerant | Pet-safe |
| Heldreich's Sage | Direct sun (at least 4-6 hours) | Occasional; drought-tolerant once established | Pet-safe |
| Helenium 'Chipperfield Orange' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days during dry periods | Toxic to pets |
| Helenium 'Coppelia' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days in dry summer weather | Toxic to pets |
| Helenium 'Floretan' | Direct sun (at least 4-6 hours) | Every 5-7 days; maintain consistent soil moisture through summer | Toxic to pets |
| Helenium 'Helbro' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water every 3-5 days during dry summer spells | Toxic to pets |
| Helenium 'Moerheim Beauty' | Direct sun (at least 4-6 hours) | Keep evenly moist; water every 4-7 days, more often in dry heat | Toxic to pets |
| Helenium 'Pumilum Magnificum' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days in dry weather | Toxic to pets |
| Helenium 'Riverton Beauty' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days in warm, dry weather | Toxic to pets |
| Helenium 'Rotgold' | Direct sun (at least 4-6 hours) | Keep evenly moist; water when the top 2-3 cm of soil is dry, roughly every 4-7 days in summer | Mildly toxic to pets |
| Helenium 'Rubinzwerg' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days during dry summer spells | Toxic to pets |
| Helenium 'Sahin's Early Flowerer' | Direct sun (at least 4-6 hours) | Keep consistently moist; water every 4-7 days, more in heat | Toxic to pets |
| Helenium 'Sahin's Early Flowerer' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days during dry summer spells | Toxic to pets |
| Helenium 'Short and Sassy' | Direct sun (at least 4-6 hours) | Every 5-7 days; do not allow soil to dry out completely during summer | Toxic to pets |
| Helenium 'Waldtraut' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water every 3-5 days during dry spells | Toxic to pets |
| Helenium 'Wyndley' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water every 3-5 days during dry spells | Toxic to pets |
| Helenium autumnale 'Pumilum Magnificum' | Direct sun (at least 4-6 hours) | Keep evenly moist; water when the top 2-3 cm of soil is dry, roughly every 4-7 days in summer | Mildly toxic to pets |
| Helianthus 'Lemon Queen' | Direct sun (at least 4-6 hours) | Water when the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Pet-safe |
| Helianthus × multiflorus 'Loddon Gold' | Direct sun (at least 4-6 hours) | About once or twice a week, keeping soil moist in summer | Pet-safe |
| Helianthus decapetalus 'Flore Pleno' | Direct sun (at least 4-6 hours) | Water when the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Pet-safe |
| Helianthus salicifolius | Direct sun (at least 4-6 hours) | Water when the top 3-4 cm of soil is dry, roughly every 7-10 days; drought-tolerant once established | Pet-safe |
| Hellebore | Medium indirect light (a couple of metres from a window) | Weekly watering until established | Toxic to pets |
| Hellebore 'Penny's Pink' | Medium indirect light (a couple of metres from a window) | Keep evenly moist during establishment and dry spells; established clumps are moderately drought-tolerant | Toxic to pets |
| Helleborus × hybridus | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry; roughly weekly in the first year, then only in dry spells once established | Toxic to pets |
| Helleborus foetidus | Medium indirect light (a couple of metres from a window) | When the top few centimetres of soil dry out; weekly while establishing, then rarely once settled | Toxic to pets |
| Helleborus orientalis 'Ivory Prince' | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry; weekly while establishing, then during dry spells | Toxic to pets |
| Helleri Holly | Direct sun (at least 4-6 hours) | Weekly deep watering while establishing, then every 7-14 days during dry weather | Toxic to pets |
| Hemiboea subcapitata | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Mildly toxic to pets |
| Hemlock Water Dropwort | Direct sun (at least 4-6 hours) | Constantly wet; wetland marginal or in-water species | Toxic to pets |
| Hemlock Water Parsnip | Direct sun (at least 4-6 hours) | Continuously — must have saturated or inundated soil | Toxic to pets |
| Henry's honeysuckle | Medium indirect light (a couple of metres from a window) | Weekly during dry periods; established plants are relatively drought-tolerant | Mildly toxic to pets |
| Henry's Lily | Medium indirect light (a couple of metres from a window) | When top 3–4 cm of soil feels dry | Toxic to pets |
| Henry's Lily | Bright indirect light (just back from a sunny window) | Regular during growth, approximately every 7–10 days in dry weather; reduce after dormancy | Toxic to pets |
| Henry's Lime | Bright indirect light (just back from a sunny window) | Weekly during establishment; deep watering every 2–3 weeks in dry periods | Pet-safe |
| Herb Robert | Medium indirect light (a couple of metres from a window) | Low to moderate; water only during prolonged dry spells | Pet-safe |
| Heritage River Birch | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week in the first 2 years; established trees prefer consistently moist soil | Pet-safe |
| Hermann's Pride Yellow Archangel | Medium indirect light (a couple of metres from a window) | Every 7–14 days during the growing season; reduce in winter | Mildly toxic to pets |
| Hermit Primulina | Medium indirect light (a couple of metres from a window) | Allow the top half of the compost to dry between waterings | Mildly toxic to pets |
| Herrenhausen Oregano | Direct sun (at least 4-6 hours) | Every 10–14 days when established; more frequently for young plants | Pet-safe |
| Heuchera 'Amber Waves' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-10 days in the growing season | Mildly toxic to pets |
| Heuchera 'Berry Smoothie' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days during active growth | Mildly toxic to pets |
| Heuchera 'Carnival Rose Granita' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Heuchera 'Citronelle' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Mildly toxic to pets |
| Heuchera 'Dolce Blackcurrant' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-9 days in the growing season | Mildly toxic to pets |
| Heuchera 'Dolce Cinnamon Curls' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days during active growth | Mildly toxic to pets |
| Heuchera 'Fire Alarm' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days in the growing season | Mildly toxic to pets |
| Heuchera 'Galaxy' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-9 days during growth | Mildly toxic to pets |
| Heuchera 'Georgia Peach' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days during active growth | Mildly toxic to pets |
| Heuchera 'Grape Expectations' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-9 days during the growing season | Mildly toxic to pets |
| Heuchera 'Green Spice' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Hollywood' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Key Lime Pie' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Lime Marmalade' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Mildly toxic to pets |
| Heuchera 'Mahogany' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Marmalade' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Heuchera 'Midnight Rose' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Miracle' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Mocha' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Northern Exposure Amber' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Peach Flambe' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Pewter Moon' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Plum Pudding' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-9 days in summer | Mildly toxic to pets |
| Heuchera 'Purple Petticoats' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Quicksilver' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Raspberry Ice' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Rave On' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season | Pet-safe |
| Heuchera 'Saturn' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Heuchera 'Silver Scrolls' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Heuchera 'Sparkling Burgundy' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Heuchera 'Sugar Berry' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Heuchera 'Tiramisu' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days during growth | Mildly toxic to pets |
| Heuchera 'Venus' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Heuchera villosa 'Autumn Bride' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Pet-safe |
| Heucherella 'Tapestry' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, about every 5-7 days in summer | Pet-safe |
| Heucherella Brass Lantern | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Pet-safe |
| Heucherella Stoplight | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water deeply once or twice a week in dry spells | Pet-safe |
| Heucherella Sunrise Falls | Medium indirect light (a couple of metres from a window) | Keep evenly moist; in containers and baskets water more often, even daily in summer heat | Pet-safe |
| Heucherella Sweet Tea | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water deeply once or twice a week in dry weather | Pet-safe |
| Heuffel's Houseleek | Direct sun (at least 4-6 hours) | Low — allow to dry between waterings | Mildly toxic to pets |
| Hiba Arborvitae | Bright indirect light (just back from a sunny window) | Every 5–10 days; never allow soil to dry out completely | Mildly toxic to pets |
| Hibiscus | Direct sun (at least 4-6 hours) | Deep watering every 5-7 days, more in heat | Pet-safe |
| Hibiscus syriacus 'Aphrodite' | Direct sun (at least 4-6 hours) | Weekly while establishing; every 10-14 days once mature unless rainfall is sparse | Pet-safe |
| Hibiscus syriacus 'Blue Bird' | Direct sun (at least 4-6 hours) | Water weekly during the first two seasons and in summer droughts; established plants are moderately drought-tolerant | Pet-safe |
| Hibiscus syriacus 'Helene' | Direct sun (at least 4-6 hours) | Water weekly while establishing and during summer drought; moderately drought-tolerant once mature | Pet-safe |
| Hibiscus syriacus 'Minerva' | Direct sun (at least 4-6 hours) | Water weekly during establishment and summer drought; moderately drought-tolerant once established | Pet-safe |
| Hicksii Yew | Medium indirect light (a couple of metres from a window) | Every 7-10 days while establishing, then as needed | Toxic to pets |
| Himalayan Cassiope | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water before the top 2 cm of growing medium dries out. | Mildly toxic to pets |
| Himalayan Cotoneaster | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry; established plants are drought-tolerant once settled | Toxic to pets |
| Himalayan Cypress | Direct sun (at least 4-6 hours) | Weekly while establishing, then only in dry spells | Mildly toxic to pets |
| Himalayan Inula | Bright indirect light (just back from a sunny window) | 2-3 times per week; maintain consistent moisture | Pet-safe |
| Himalayan pieris | Bright indirect light (just back from a sunny window) | Regular; keep consistently moist | Toxic to pets |
| Himalayan Pieris Wakehurst | Bright indirect light (just back from a sunny window) | Water every 7–10 days; do not allow to dry out, particularly during spring growth flush | Toxic to pets |
| Himalayan Yew | Medium indirect light (a couple of metres from a window) | Weekly during establishment; every 1–2 weeks once established | Toxic to pets |
| Hinoki Cypress | Direct sun (at least 4-6 hours) | Every 5-7 days while establishing, then when the top few cm of soil dry | Mildly toxic to pets |
| Hinoki Cypress Bonsai | Direct sun (at least 4-6 hours) | When the top 2 cm of soil begins to dry, often daily in summer | Mildly toxic to pets |
| Hirta Toad Lily | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water when the surface begins to dry, typically once or twice a week in summer | Mildly toxic to pets |
| Histrioides Iris | Direct sun (at least 4-6 hours) | Moderate in late winter and spring; dry in summer | Toxic to pets |
| Hoary Plantain | Direct sun (at least 4-6 hours) | Rarely; established plants are drought-tolerant | Pet-safe |
| Hoary Stock | Direct sun (at least 4-6 hours) | Weekly, allowing soil to dry slightly between waterings | Pet-safe |
| Hogweed | Bright indirect light (just back from a sunny window) | Regular during establishment; drought-tolerant once established | Mildly toxic to pets |
| Holger Juniper | Direct sun (at least 4-6 hours) | Water regularly the first season; afterward only in extended drought | Toxic to pets |
| Hollow Joe Pye Weed | Direct sun (at least 4-6 hours) | Keep soil reliably moist; water weekly or more during dry weather | Pet-safe |
| Hollow-Rooted Fumewort | Medium indirect light (a couple of metres from a window) | Rainfall-dependent during spring growth; completely dry in summer dormancy | Toxic to pets |
| Hollyhock | Direct sun (at least 4-6 hours) | Weekly during active growth; reduce in autumn and winter | Pet-safe |
| Holmstrup Arborvitae | Direct sun (at least 4-6 hours) | Two to three times weekly when young; weekly once established | Mildly toxic to pets |
| Honesty | Medium indirect light (a couple of metres from a window) | Twice weekly in dry spells; keep soil consistently moist | Mildly toxic to pets |
| Honey Garlic | Bright indirect light (just back from a sunny window) | Low; rainfall usually sufficient once established in the UK | Toxic to pets |
| Honeysuckle Fuchsia | Bright indirect light (just back from a sunny window) | Daily in active growth; less in winter | Pet-safe |
| Hooded Dendrobium | Bright indirect light (just back from a sunny window) | Abundant in summer growth; nearly withheld over the deciduous winter rest | Pet-safe |
| Hooded-leaf Pelargonium | Direct sun (at least 4-6 hours) | Water when the top 3–4 cm of compost is dry, approximately every 7–12 days in the growing season; keep barely moist in winter | Toxic to pets |
| Hoogendorn Holly | Direct sun (at least 4-6 hours) | Weekly deep watering when young, then every 7-14 days in dry weather | Toxic to pets |
| Hook Sedge | Direct sun (at least 4-6 hours) | Keep evenly moist; water weekly in dry spells and don't let containers fully dry | Mildly toxic to pets |
| Hooker's Inula | Bright indirect light (just back from a sunny window) | 2 times per week; tolerates periodic damp conditions | Pet-safe |
| Hooker's Orchid Cactus | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, approximately every 7-14 days in spring and summer; reduce to once every 3-4 weeks in autumn and winter | Pet-safe |
| Hoop Petticoat Daffodil | Direct sun (at least 4-6 hours) | Regular during active growth; dry in summer dormancy | Toxic to pets |
| Hoop Petticoat Daffodil | Direct sun (at least 4-6 hours) | Once per week during spring growth; withhold irrigation after foliage yellows | Toxic to pets |
| Hoop Pine | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Hoopsii Blue Spruce | Direct sun (at least 4-6 hours) | Water deeply weekly for the first two to three years, then only in extended dry spells | Mildly toxic to pets |
| Horned Tulip | Direct sun (at least 4-6 hours) | Moderate during active growth; dry in summer | Toxic to pets |
| Horned violet | Bright indirect light (just back from a sunny window) | Every 5–7 days; keep evenly moist | Pet-safe |
| Horseshoe Vetch | Direct sun (at least 4-6 hours) | Rarely — established plants are very drought-tolerant | Mildly toxic to pets |
| Horstmann Korean Fir | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Hosta | Medium indirect light (a couple of metres from a window) | Keep evenly moist; roughly weekly in the ground, more often in pots or heat | Toxic to pets |
| Hosta 'Abiqua Drinking Gourd' | Low light (north window or shaded room) | When the top 3-4 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'August Moon' | Medium indirect light (a couple of metres from a window) | When the top 3 cm of soil is dry, roughly every 6-7 days in summer | Toxic to pets |
| Hosta 'Big Daddy' | Low light (north window or shaded room) | When the top 3-4 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Blue Angel' | Medium indirect light (a couple of metres from a window) | Every 5-7 days during the growing season, or when the top 3-5 cm of soil is drying | Toxic to pets |
| Hosta 'Blue Mammoth' | Low light (north window or shaded room) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Bressingham Blue' | Low light (north window or shaded room) | When the top 3 cm of soil is dry, roughly every 7 days in summer | Toxic to pets |
| Hosta 'Color Festival' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Curly Fries' | Medium indirect light (a couple of metres from a window) | When the top 2 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Diamond Tiara' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'El Nino' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7 days during the growing season | Toxic to pets |
| Hosta 'Elegans' | Medium indirect light (a couple of metres from a window) | Every 5-7 days during the growing season, or when the top 3-5 cm of soil is drying | Toxic to pets |
| Hosta 'Empress Wu' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Hosta 'Fire Island' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Hosta 'First Frost' | Medium indirect light (a couple of metres from a window) | When top 2-3 cm of soil begins to dry, about every 5-7 days, more in heat | Toxic to pets |
| Hosta 'Fortunei Aureomarginata' | Medium indirect light (a couple of metres from a window) | Every 5-7 days during the growing season, or when the top 3-5 cm of soil is drying | Toxic to pets |
| Hosta 'Fragrant Bouquet' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-7 days in summer | Toxic to pets |
| Hosta 'Frances Williams' | Medium indirect light (a couple of metres from a window) | Every 5-7 days in the growing season, or when the top 3-5 cm of soil is drying out | Toxic to pets |
| Hosta 'Fun and Games' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Golden Tiara' | Medium indirect light (a couple of metres from a window) | When the top 2 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Grand Tiara' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Great Expectations' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Hosta 'Guacamole' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Halcyon Blue' | Low light (north window or shaded room) | When the top 3 cm of soil is dry, roughly every 7-10 days in summer | Toxic to pets |
| Hosta 'Halcyon' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Invincible' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Island Charm' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'June' | Medium indirect light (a couple of metres from a window) | When top 2-3 cm of soil begins to dry, about every 5-7 days, more in heat | Toxic to pets |
| Hosta 'Krossa Regal' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7 days during the growing season | Toxic to pets |
| Hosta 'Lancifolia' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Love Pat' | Low light (north window or shaded room) | When the top 3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Midnight Rider' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Night Before Christmas' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'On Stage' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Patriot' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days through the growing season | Toxic to pets |
| Hosta 'Paul Revere' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Hosta 'Pineapple Upside Down Cake' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Praying Hands' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7 days in summer | Toxic to pets |
| Hosta 'Regal Splendor' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Remember Me' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Hosta 'Revolution' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Hosta 'Royal Standard' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Sagae' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Hosta 'Shade Fanfare' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Something Different' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Stained Glass' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Hosta 'Sum and Substance' | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Touch of Class' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7 days during the growing season | Toxic to pets |
| Hosta 'Twilight' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Undulata Albomarginata' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Ventricosa' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Hosta 'Wheel of Fortune' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-8 days in summer | Toxic to pets |
| Hosta 'Wide Brim' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Hosta sieboldiana 'Elegans' | Low light (north window or shaded room) | When top 2-3 cm of soil begins to dry, about every 5-7 days, more in heat | Toxic to pets |
| Hound's-tongue | Direct sun (at least 4-6 hours) | Rarely, once established | Toxic to pets |
| Houseleek Saxifrage | Bright indirect light (just back from a sunny window) | Low — water sparingly at all times; near-dry in summer and winter | Pet-safe |
| Houttuynia cordata | Direct sun (at least 4-6 hours) | Keep soil constantly wet to waterlogged; never let it dry out | Mildly toxic to pets |
| Houttuynia cordata 'Chameleon' | Direct sun (at least 4-6 hours) | Keep soil constantly wet to waterlogged; never allow it to dry | Mildly toxic to pets |
| Hoya | Bright indirect light (just back from a sunny window) | When the soil is mostly dry, every 10-14 days | Pet-safe |
| Hoya Pubicalyx 'Black Dragon' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of mix is dry, roughly every 7-14 days | Pet-safe |
| Hoya Pubicalyx 'Royal Hawaiian Purple' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of mix is dry, roughly every 7-14 days | Pet-safe |
| Humulus lupulus 'Aureus' | Direct sun (at least 4-6 hours) | Keep soil reliably moist in the growing season, about every 3-5 days in summer | Toxic to pets |
| Hungarian Barren Strawberry | Medium indirect light (a couple of metres from a window) | Low; drought-tolerant once established | Pet-safe |
| Hungarian Lilac | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Hungarian Oak | Direct sun (at least 4-6 hours) | Establish with regular watering in year 1–2; highly drought-tolerant once established | Mildly toxic to pets |
| Huron Sunrise Miscanthus | Direct sun (at least 4-6 hours) | Weekly in the establishment year; thereafter only during prolonged drought | Mildly toxic to pets |
| Hyacinth | Bright indirect light (just back from a sunny window) | Weekly watering during growth | Toxic to pets |
| Hyacinthus orientalis 'Carnegie' | Direct sun (at least 4-6 hours) | Moist through growth and flowering; reduce after foliage dies back | Toxic to pets |
| Hyacinthus orientalis 'City of Haarlem' | Direct sun (at least 4-6 hours) | Moist during growth and flowering; reduce after foliage dies back | Toxic to pets |
| Hyacinthus orientalis 'Delft Blue' | Direct sun (at least 4-6 hours) | Keep soil moist during growth and flowering; reduce sharply after foliage dies back | Toxic to pets |
| Hyacinthus orientalis 'Jan Bos' | Direct sun (at least 4-6 hours) | Moist through growth and flowering; reduce after foliage dies back | Toxic to pets |
| Hyacinthus orientalis 'Woodstock' | Direct sun (at least 4-6 hours) | Moist during growth and flowering; much drier after dormancy sets in | Toxic to pets |
| Hybrid trumpet vine | Direct sun (at least 4-6 hours) | Weekly during establishment; established plants are drought-tolerant | Mildly toxic to pets |
| Hydrangea | Bright indirect light (just back from a sunny window) | Deep watering 1-2 times per week, more in heat | Toxic to pets |
| Hydrangea 'Annabelle' | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water deeply 2-3 times weekly in summer, more in heat or drought | Toxic to pets |
| Hydrangea 'Annabelle' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days; more frequently in hot weather | Mildly toxic to pets |
| Hydrangea 'Blushing Bride' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil feels dry, roughly every 3-5 days in summer heat | Mildly toxic to pets |
| Hydrangea 'Bobo' | Bright indirect light (just back from a sunny window) | When the top 3 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Hydrangea 'Endless Summer' | Bright indirect light (just back from a sunny window) | Keep consistently moist; water deeply 2-3 times weekly in heat | Toxic to pets |
| Hydrangea 'Endless Summer' | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water deeply 2-3 times weekly in summer heat, more for containers | Toxic to pets |
| Hydrangea 'Incrediball' | Bright indirect light (just back from a sunny window) | When the top 5 cm of soil is dry, about 2-3 times per week in summer | Toxic to pets |
| Hydrangea 'Let's Dance Rhythmic Blue' | Bright indirect light (just back from a sunny window) | When the top 3 cm of soil is dry, roughly every 5-7 days during the growing season | Mildly toxic to pets |
| Hydrangea 'Limelight' | Direct sun (at least 4-6 hours) | Keep soil moist while establishing; water deeply once or twice weekly in summer, less once established | Toxic to pets |
| Hydrangea 'Limelight' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Hydrangea 'Little Lime' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, about 1-2 times per week | Toxic to pets |
| Hydrangea 'Nikko Blue' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 5-7 days during the growing season | Mildly toxic to pets |
| Hydrangea 'Pee Gee' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Hydrangea 'PeeWee' | Bright indirect light (just back from a sunny window) | When the top 5 cm of soil is dry, about once per week | Toxic to pets |
| Hydrangea 'Pinky Winky' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, about 1-2 times per week | Toxic to pets |
| Hydrangea 'Quick Fire' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Hydrangea 'Snowflake' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Hydrangea 'Strawberry Sundae' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Hydrangea 'Tardiva' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Hydrangea 'Vanilla Strawberry' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly 1-2 times per week | Toxic to pets |
| Hydrangea aspera 'Villosa' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply every 5-7 days in dry summer spells | Toxic to pets |
| Hydrocharis morsus-ranae | Direct sun (at least 4-6 hours) | Free-floating; keep on the surface of still or slow water | Mildly toxic to pets |
| Hylotelephium 'Autumn Joy' | Direct sun (at least 4-6 hours) | Roughly every 10-14 days in its first season; established plants rarely need watering | Pet-safe |
| Hylotelephium 'Purple Emperor' | Direct sun (at least 4-6 hours) | Every 10-14 days when young; established plants need little to no watering | Pet-safe |
| Hylotelephium spectabile 'Brilliant' | Direct sun (at least 4-6 hours) | Every 10-14 days while establishing; mature clumps rely on rainfall | Pet-safe |
| Hylotelephium telephium 'Munstead Dark Red' | Direct sun (at least 4-6 hours) | Every 10-14 days while establishing; mature plants are largely self-reliant | Pet-safe |
| Iara's Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in active growth; almost none during dormancy | Mildly toxic to pets |
| Iberian Cranesbill | Bright indirect light (just back from a sunny window) | Weekly in spring and summer; occasional in autumn | Pet-safe |
| Ice Dance Sedge | Medium indirect light (a couple of metres from a window) | Keep moist while establishing; water deeply weekly in dry spells | Mildly toxic to pets |
| Ice Follies Daffodil | Direct sun (at least 4-6 hours) | Moderate during autumn–spring; dry in summer dormancy | Toxic to pets |
| Ice Plant | Direct sun (at least 4-6 hours) | Every 10-14 days during establishment; mature clumps rely on rainfall | Pet-safe |
| Iceberg Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Idaho fescue | Direct sun (at least 4-6 hours) | Very low; water every 2–3 weeks during the first season; monthly or less once established | Pet-safe |
| Illinois Tick Trefoil | Direct sun (at least 4-6 hours) | Deep watering every 10–14 days during the first growing season; drought-tolerant once established | Pet-safe |
| Illumination Periwinkle | Bright indirect light (just back from a sunny window) | Once or twice weekly; more frequently in containers or hot weather | Toxic to pets |
| Impatiens | Medium indirect light (a couple of metres from a window) | Twice-weekly watering | Pet-safe |
| Impatiens balsamina | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Pet-safe |
| Impatiens hawkeri 'SunPatiens Compact Hot Coral' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, often daily in full sun during summer | Pet-safe |
| Impatiens hawkeri 'SunPatiens Spreading White' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, often daily in full sun and in baskets | Pet-safe |
| Impatiens walleriana 'Xtreme Salmon' | Low light (north window or shaded room) | When the top 1-2 cm of soil begins to dry, often every 1-3 days in summer | Pet-safe |
| Incense Cedar | Direct sun (at least 4-6 hours) | Every 7–10 days when young; established trees are drought-tolerant and rely mainly on rainfall | Mildly toxic to pets |
| Indian Blanket | Direct sun (at least 4-6 hours) | Every 1–2 weeks; drought-tolerant once established | Pet-safe |
| Indian Cucumber Root | Low light (north window or shaded room) | Consistently moist; water whenever the top 2–3 cm of soil begins to dry during the growing season | Mildly toxic to pets |
| indian grass | Direct sun (at least 4-6 hours) | Rarely once established; water during the first growing season to aid establishment | Pet-safe |
| Indian Head Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 7-10 days in spring and summer; every 3-4 weeks in autumn; minimal in winter | Pet-safe |
| Indian Head Notocactus | Direct sun (at least 4-6 hours) | When soil is completely dry, roughly every 10-14 days in the active growing season; reduce to once every 5-8 weeks in winter | Pet-safe |
| Indian Summer black-eyed Susan | Direct sun (at least 4-6 hours) | Weekly; allow the top 2–3 cm of soil to dry slightly between waterings | Pet-safe |
| Indian Summer Black-Eyed Susan | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Inflated Rock Rose | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; weekly in the first season | Mildly toxic to pets |
| Intense Blue Fescue | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; minimal once established | Mildly toxic to pets |
| Intergeneric Aliceara 'Pacific Sabre' | Bright indirect light (just back from a sunny window) | Water thoroughly when the top of the bark approaches dryness, typically every 5-7 days | Pet-safe |
| Interrupted Sage | Direct sun (at least 4-6 hours) | Every 7–14 days in summer; very sparingly in winter | Mildly toxic to pets |
| Intrigue Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times weekly, about 4-5 litres per plant | Pet-safe |
| Ipomoea batatas 'Blackie' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, often every 2-3 days in containers in summer | Toxic to pets |
| Ipomoea lobata | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-6 days in summer | Toxic to pets |
| Ipomoea nil 'Scarlett O'Hara' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 3-5 days in summer | Toxic to pets |
| Ipomoea purpurea | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 3-5 days in summer heat | Toxic to pets |
| Ipomoea quamoclit | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 4-6 days in summer | Toxic to pets |
| Ipomoea tricolor 'Heavenly Blue' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-5 days in warm weather | Toxic to pets |
| Iris | Direct sun (at least 4-6 hours) | Weekly watering during growth | Toxic to pets |
| Iris 'Benton Susan' | Direct sun (at least 4-6 hours) | Water at planting and during establishment, then only in prolonged drought; established clumps are drought-tolerant | Toxic to pets |
| Iris 'Black Gamecock' | Direct sun (at least 4-6 hours) | Keep consistently wet; tolerates standing water and never fully dry out | Toxic to pets |
| Iris 'Clarence' | Direct sun (at least 4-6 hours) | Keep moist through spring and late summer to support rebloom; do not waterlog | Toxic to pets |
| Iris 'Immortality' | Direct sun (at least 4-6 hours) | Keep evenly moist through spring and late summer to support rebloom; avoid waterlogging | Toxic to pets |
| Iris 'Jane Phillips' | Direct sun (at least 4-6 hours) | Water deeply during spring growth and after planting; keep drier in summer | Toxic to pets |
| Iris 'Katharine Hodgkin' | Direct sun (at least 4-6 hours) | Water during autumn-to-spring growth; keep dry in summer dormancy | Toxic to pets |
| Iris ensata | Direct sun (at least 4-6 hours) | Keep soil constantly moist in spring and summer; drier in winter | Toxic to pets |
| Iris laevigata | Direct sun (at least 4-6 hours) | Permanently wet; thrives in 0-15 cm of standing water year-round | Toxic to pets |
| Iris laevigata 'Variegata' | Direct sun (at least 4-6 hours) | Permanently wet; thrives in 0-15 cm of standing water year-round | Toxic to pets |
| Iris pseudacorus | Direct sun (at least 4-6 hours) | Permanently wet; thrives in 0-30 cm of standing water | Toxic to pets |
| Iris pseudacorus 'Variegatus' | Direct sun (at least 4-6 hours) | Keep permanently wet; never let the rootzone dry out | Toxic to pets |
| Iris reticulata 'Harmony' | Direct sun (at least 4-6 hours) | Water during autumn-to-spring growth; keep dry in summer dormancy | Toxic to pets |
| Iris versicolor | Direct sun (at least 4-6 hours) | Keep consistently wet to shallowly submerged | Toxic to pets |
| Iris virginica | Direct sun (at least 4-6 hours) | Keep wet to shallowly submerged year-round | Toxic to pets |
| Irish Fleabane | Direct sun (at least 4-6 hours) | Every 7-10 days during the growing season; less in winter | Mildly toxic to pets |
| Irish heath | Direct sun (at least 4-6 hours) | Weekly while establishing; every 2–3 weeks once established | Pet-safe |
| Irish Heath Irish Dusk | Direct sun (at least 4-6 hours) | Regular during establishment; moderate once settled | Mildly toxic to pets |
| Irish Ivy | Low light (north window or shaded room) | Water every 7-14 days during establishment; established plants are drought-tolerant and rarely need supplemental irrigation | Toxic to pets |
| Iron Butterfly Foamflower | Medium indirect light (a couple of metres from a window) | Once or twice per week during the growing season; water sparingly in winter. | Mildly toxic to pets |
| Iron Butterfly Tiarella | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water deeply once or twice a week when rainfall is short | Mildly toxic to pets |
| Italian aster | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; drought-tolerant in summer | Pet-safe |
| Italian Cypress | Direct sun (at least 4-6 hours) | Every 1-2 weeks while establishing, then minimal | Mildly toxic to pets |
| Italian Gladiolus | Direct sun (at least 4-6 hours) | Moderate during growth; dry when dormant | Toxic to pets |
| Italian jasmine | Bright indirect light (just back from a sunny window) | Every 7–14 days; drought-tolerant once established | Mildly toxic to pets |
| Italian Sage Phlomis | Direct sun (at least 4-6 hours) | Low — once every 2–3 weeks once established | Mildly toxic to pets |
| Itea virginica | Bright indirect light (just back from a sunny window) | Keep soil moist; water weekly or more in dry spells, tolerant of wet ground | Mildly toxic to pets |
| Itea virginica 'Henry's Garnet' | Bright indirect light (just back from a sunny window) | Keep soil moist; water weekly or more in dry weather, tolerant of wet ground | Mildly toxic to pets |
| Itea virginica 'Little Henry' | Bright indirect light (just back from a sunny window) | Keep soil moist; water weekly or more in dry spells, tolerant of wet ground | Mildly toxic to pets |
| Ithuriel's Spear | Bright indirect light (just back from a sunny window) | Moderate in spring during active growth; dry summer dormancy required | Mildly toxic to pets |
| Ithuriel's Spear | Direct sun (at least 4-6 hours) | Moderate water during spring growth; dry summer rest required | Mildly toxic to pets |
| Itoh Peony 'Bartzella' | Direct sun (at least 4-6 hours) | Deeply once a week during growth and budding; established plants tolerate short dry spells | Toxic to pets |
| Ivan Cranesbill | Medium indirect light (a couple of metres from a window) | Once or twice a week in dry spells; less in cooler or wetter periods | Pet-safe |
| Ivory Primulina | Medium indirect light (a couple of metres from a window) | Allow the top half of compost to dry before rewatering | Mildly toxic to pets |
| Ivory Sea Holly | Direct sun (at least 4-6 hours) | Moderate — water regularly during the growing season; reduce in winter | Pet-safe |
| Ivy-Leaved Cyclamen | Medium indirect light (a couple of metres from a window) | Drought-tolerant once established; rely entirely on natural rainfall | Toxic to pets |
| Ivy-leaved Duckweed | Medium indirect light (a couple of metres from a window) | Permanently submerged | Pet-safe |
| Ivyleaf morning glory | Direct sun (at least 4-6 hours) | Once or twice a week; allow soil to dry slightly between waterings | Toxic to pets |
| Jack-in-the-Pulpit | Low light (north window or shaded room) | Keep the soil consistently moist throughout the growing season, watering whenever the surface begins to dry; it tolerates short dry spells but resents drought. | Toxic to pets |
| Jacobinia Carnea | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, typically every 4-7 days in growth | Mildly toxic to pets |
| Jacqueline Postill Daphne | Bright indirect light (just back from a sunny window) | Roughly every 7-10 days in the growing season, allowing the top 3-5 cm to dry between waterings | Toxic to pets |
| Janke's Gesneriad | Medium indirect light (a couple of metres from a window) | Water at the root zone only when the soil approaches dryness, roughly every 10–14 days in the growing season | Mildly toxic to pets |
| Japanese Anemone 'Honorine Jobert' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Japanese Apricot | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil dries, often daily in summer | Toxic to pets |
| Japanese Arborvitae | Direct sun (at least 4-6 hours) | Regular — keep soil evenly moist; do not allow to dry out completely | Pet-safe |
| Japanese astilbe | Medium indirect light (a couple of metres from a window) | Twice per week in active growth; weekly in cooler seasons | Pet-safe |
| Japanese barberry | Direct sun (at least 4-6 hours) | Every 1–2 weeks during establishment; drought-tolerant once established | Mildly toxic to pets |
| Japanese Beech | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil begins to dry, often daily in summer | Mildly toxic to pets |
| Japanese Beech Fern | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water when the top 2-3 cm begin to dry, roughly weekly during dry periods | Mildly toxic to pets |
| Japanese Big-Leaf Magnolia | Bright indirect light (just back from a sunny window) | Weekly during dry periods; established trees are moderately drought-tolerant | Pet-safe |
| Japanese Black Pine | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is approaching dry, often daily in summer heat | Mildly toxic to pets |
| Japanese Black Pine 'Kotobuki' | Direct sun (at least 4-6 hours) | When the soil surface is approaching dry, then water thoroughly | Mildly toxic to pets |
| Japanese Black Pine 'Thunderhead' | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry; allow slight drying between waterings | Mildly toxic to pets |
| Japanese Blood Grass | Direct sun (at least 4-6 hours) | Keep soil moist; water 1-2 times weekly, more in heat | Mildly toxic to pets |
| Japanese box | Bright indirect light (just back from a sunny window) | Weekly when young; every 10–14 days once established | Toxic to pets |
| Japanese Camellia | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry; keep evenly moist in late summer | Pet-safe |
| Japanese Camellia 'Nuccio's Pearl' | Bright indirect light (just back from a sunny window) | About weekly, more in heat and during budding; water when the top 3-5 cm of soil is dry | Pet-safe |
| Japanese Catmint | Medium indirect light (a couple of metres from a window) | Every 5–7 days; do not allow to dry out completely | Pet-safe |
| Japanese Cedar 'Cristata' | Direct sun (at least 4-6 hours) | Keep evenly moist; weekly in dry spells, more for young plants | Mildly toxic to pets |
| Japanese Cedar 'Elegans' | Direct sun (at least 4-6 hours) | Keep evenly moist; water weekly in dry spells, more for young plants | Mildly toxic to pets |
| Japanese Cedar 'Globosa Nana' | Direct sun (at least 4-6 hours) | Keep evenly moist; weekly in dry weather, more in containers | Mildly toxic to pets |
| Japanese Cedar 'Spiralis' | Direct sun (at least 4-6 hours) | Keep evenly moist; weekly in dry weather, more for young or potted plants | Mildly toxic to pets |
| Japanese Cedar 'Vilmoriniana' | Direct sun (at least 4-6 hours) | Keep evenly moist; weekly in dry spells, attentive in troughs | Mildly toxic to pets |
| Japanese Cedar Bonsai | Direct sun (at least 4-6 hours) | When the top 2 cm of soil starts to dry, often daily in summer | Mildly toxic to pets |
| Japanese Cornel Dogwood | Direct sun (at least 4-6 hours) | Regular watering while establishing; drought-tolerant once mature | Pet-safe |
| Japanese Fairy Bells | Medium indirect light (a couple of metres from a window) | Regular; keep soil evenly moist throughout the growing season. | Mildly toxic to pets |
| Japanese Flowering Cherry Bonsai | Direct sun (at least 4-6 hours) | When the top 2 cm of soil starts to dry, often daily in summer | Toxic to pets |
| Japanese Garden Juniper | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is just dry, frequently in summer | Toxic to pets |
| Japanese Hornbeam | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil starts to dry, often daily in summer | Mildly toxic to pets |
| Japanese kerria | Medium indirect light (a couple of metres from a window) | Weekly during establishment; drought-tolerant once established | Mildly toxic to pets |
| Japanese Larch | Direct sun (at least 4-6 hours) | When the surface just begins to dry, often once or twice daily in summer | Mildly toxic to pets |
| Japanese Maple | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, about weekly and more in heat | Mildly toxic to pets |
| Japanese Maple 'Crimson Queen' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, about weekly and more in heat or pots | Mildly toxic to pets |
| Japanese Maple 'Dissectum' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, often weekly in summer | Pet-safe |
| Japanese Maple 'Osakazuki' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, around weekly in dry weather | Pet-safe |
| Japanese Maple 'Sango Kaku' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly weekly in dry spells | Pet-safe |
| Japanese Mazus | Direct sun (at least 4-6 hours) | Every 3–5 days; prefers moist, consistently watered soil | Mildly toxic to pets |
| Japanese morning glory | Direct sun (at least 4-6 hours) | 2–3 times per week in containers; once a week in garden beds during dry spells | Toxic to pets |
| Japanese Nutmeg Yew | Medium indirect light (a couple of metres from a window) | Every 7–10 days when establishing; established trees rely on rainfall with supplemental watering in dry spells | Mildly toxic to pets |
| Japanese Pieris | Bright indirect light (just back from a sunny window) | Keep evenly moist; water weekly in dry spells and never let it dry out | Toxic to pets |
| Japanese Pieris 'Forest Flame' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water weekly during dry spells, more in containers | Toxic to pets |
| Japanese Pieris 'Mountain Fire' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry; keep evenly moist, particularly while establishing | Toxic to pets |
| Japanese Pieris Flamingo | Bright indirect light (just back from a sunny window) | Water deeply every 7–10 days; more frequently in hot, dry spells | Toxic to pets |
| Japanese Plum Yew | Medium indirect light (a couple of metres from a window) | Keep evenly moist; weekly in dry spells, more while establishing | Mildly toxic to pets |
| Japanese Privet Bonsai | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil dries, often daily in summer | Toxic to pets |
| Japanese Quince Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil starts to dry, often daily in summer | Mildly toxic to pets |
| Japanese Rose | Direct sun (at least 4-6 hours) | Weekly while young, then drought-tolerant once established | Pet-safe |
| Japanese Sage | Medium indirect light (a couple of metres from a window) | Regular during growing season; reduce in winter | Pet-safe |
| Japanese Show Lily | Bright indirect light (just back from a sunny window) | Regular during active growth, roughly every 5–7 days in dry spells; reduce after foliage dies back | Toxic to pets |
| Japanese Solomon's Seal | Medium indirect light (a couple of metres from a window) | Every 5–7 days during growth; minimal when dormant | Mildly toxic to pets |
| Japanese Spirea | Direct sun (at least 4-6 hours) | Once per week while establishing; drought-tolerant when established | Pet-safe |
| Japanese Spirea 'Anthony Waterer' | Direct sun (at least 4-6 hours) | Weekly during the first season, then only in prolonged dry spells | Mildly toxic to pets |
| Japanese Spirea 'Goldflame' | Direct sun (at least 4-6 hours) | Water when the top 5 cm of soil is dry, about weekly while establishing | Pet-safe |
| Japanese Spurge | Low light (north window or shaded room) | Weekly during establishment (first two growing seasons); monthly or during dry spells once established | Mildly toxic to pets |
| Japanese Tree Lilac | Direct sun (at least 4-6 hours) | Weekly while young, then only in drought | Mildly toxic to pets |
| Japanese Tree Lilac | Direct sun (at least 4-6 hours) | Every 7-14 days during the first two seasons; drought-tolerant once established | Mildly toxic to pets |
| Japanese Tree Lilac 'Ivory Silk' | Direct sun (at least 4-6 hours) | Weekly deep soakings for the first two years, then during droughts | Pet-safe |
| Japanese Umbrella Pine | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly weekly while young, less once established | Mildly toxic to pets |
| Japanese White Pine | Direct sun (at least 4-6 hours) | Water only when the soil surface has begun to dry; pines prefer a slightly drier regime | Mildly toxic to pets |
| Japanese White Pine 'Glauca' | Direct sun (at least 4-6 hours) | Water young trees weekly in dry weather; established trees seldom | Mildly toxic to pets |
| Japanese Witch Hazel | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-14 days in the growing season | Pet-safe |
| Japanese Wood Poppy | Medium indirect light (a couple of metres from a window) | Regular; keep soil evenly moist during the growing season | Mildly toxic to pets |
| Japanese Zelkova | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil starts to dry, often daily in summer | Mildly toxic to pets |
| Jasmine (Pink Jasmine) | Bright indirect light (just back from a sunny window) | When the top 2-3cm of soil feels dry, roughly weekly in growth | Pet-safe |
| Jasminum beesianum | Direct sun (at least 4-6 hours) | Keep evenly moist while establishing; water in prolonged dry spells once mature | Pet-safe |
| Jasminum mesnyi | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 5-7 days in summer | Pet-safe |
| Jasminum nudiflorum | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry out, about every 7-10 days while establishing | Pet-safe |
| Jasminum sambac 'Grand Duke of Tuscany' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days in growth | Pet-safe |
| Jasminum sambac 'Maid of Orleans' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-6 days in warm growth | Pet-safe |
| Jeddeloh Hemlock | Bright indirect light (just back from a sunny window) | Regular — do not allow to dry out | Pet-safe |
| Jelena witch hazel | Bright indirect light (just back from a sunny window) | Regularly during establishment; thereafter water during summer dry spells | Mildly toxic to pets |
| Jelena Witch Hazel | Bright indirect light (just back from a sunny window) | Deeply once or twice a week during the first growing season; established plants roughly every 10-14 days or as the top 5 cm dries | Mildly toxic to pets |
| Jerusalem Sage | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water deeply once every 2–3 weeks in the first growing season, then rely on rainfall in most UK and Mediterranean-climate US regions. | Mildly toxic to pets |
| Joe-Pye Weed | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days in dry weather | Toxic to pets |
| Johannes Cape Primrose | Medium indirect light (a couple of metres from a window) | Every 5-8 days in active growth; every 2-3 weeks in winter | Pet-safe |
| Johnny Jump Up | Bright indirect light (just back from a sunny window) | When the top 1–2 cm of soil is dry, roughly every 5–7 days | Mildly toxic to pets |
| Jolly Bee Cranesbill | Bright indirect light (just back from a sunny window) | Regular; keep moderately moist | Mildly toxic to pets |
| Jonquil | Direct sun (at least 4-6 hours) | Moderate during autumn–spring growth; very dry during summer dormancy | Toxic to pets |
| Joseph's coat | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Joseph's Coat Amaranth | Direct sun (at least 4-6 hours) | When the top 3 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Josephine's Lily | Direct sun (at least 4-6 hours) | Water from flower-scape emergence (late summer) through leaf period (winter–spring); completely dry from late spring to late summer | Toxic to pets |
| Jubilee Celebration Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season; more in heat | Pet-safe |
| Julia Child Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Jungfrau Saxifrage | Bright indirect light (just back from a sunny window) | Water moderately; allow soil to partially dry between waterings and reduce in winter. | Pet-safe |
| Jungle Geranium | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of soil feels dry, roughly 1-2 times per week in growth | Pet-safe |
| Juniper-leaved Thrift | Direct sun (at least 4-6 hours) | Every 10–14 days during growth; very sparingly in winter | Pet-safe |
| Juno Iris | Direct sun (at least 4-6 hours) | Moderate from early spring to late spring; completely dry mid-summer to mid-autumn | Toxic to pets |
| Jupiter's Distaff | Medium indirect light (a couple of metres from a window) | Regularly in dry spells, especially in sun | Pet-safe |
| Just Joey Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly while in growth | Pet-safe |
| Kahili Ginger | Bright indirect light (just back from a sunny window) | Water freely in spring and summer (every 3–5 days); reduce sharply in autumn and keep barely moist over winter | Mildly toxic to pets |
| Kalanchoe | Direct sun (at least 4-6 hours) | When the soil is dry, every 10-14 days | Toxic to pets |
| Kalanchoe 'Calandiva' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is fully dry, roughly every 7-14 days | Toxic to pets |
| Kalanchoe 'Kerinci' | Bright indirect light (just back from a sunny window) | When the soil is dry to about halfway down, every 10-14 days | Toxic to pets |
| Kamchatka Bugbane | Medium indirect light (a couple of metres from a window) | 2–3 times per week in growing season; weekly when dormant | Mildly toxic to pets |
| Kamchatka Stonecrop | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is fully dry, roughly every 10-14 days; very infrequently once established | Pet-safe |
| Karl Foerster Feather Reed Grass | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry, roughly weekly; tolerant of occasional wet ground | Pet-safe |
| Karl Foerster Feather Reed Grass | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 2 weeks once established | Pet-safe |
| Karl Foerster Reed Grass | Bright indirect light (just back from a sunny window) | Every 7-14 days during the first season; established plants need water only in prolonged drought | Pet-safe |
| Karley Rose Fountain Grass | Direct sun (at least 4-6 hours) | Water every 7-14 days during establishment; established plants tolerate drought and need watering only in prolonged dry spells | Mildly toxic to pets |
| Karley Rose Oriental Fountain Grass | Direct sun (at least 4-6 hours) | Weekly in the first season, then moderate watering during dry periods | Pet-safe |
| Kashmir Cypress | Direct sun (at least 4-6 hours) | Regularly; moist but well-drained | Mildly toxic to pets |
| Kashmir Gentian | Bright indirect light (just back from a sunny window) | Keep evenly moist through the growing season | Mildly toxic to pets |
| Kashmir rowan | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once mature | Mildly toxic to pets |
| Katz Sakura stock | Direct sun (at least 4-6 hours) | Every 3–5 days; keep soil evenly moist but never waterlogged | Pet-safe |
| Kauri | Bright indirect light (just back from a sunny window) | Every 5–7 days in spring/summer; reduce to every 10–14 days in winter | Pet-safe |
| Keisk's Leucothoe | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season; sensitive to both drought and waterlogging | Toxic to pets |
| Keiske's Leucothoe | Medium indirect light (a couple of metres from a window) | Once or twice a week in the growing season, less in winter | Toxic to pets |
| Kelsey's Phlox | Direct sun (at least 4-6 hours) | Low to moderate — allow soil to dry between waterings | Mildly toxic to pets |
| Kentucky wisteria | Direct sun (at least 4-6 hours) | Weekly during the first growing season; drought-tolerant once established | Toxic to pets |
| Keteleeria davidiana | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing; established trees rely largely on rainfall with watering in drought | Mildly toxic to pets |
| Kidney Vetch | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Mildly toxic to pets |
| Kiftsgate Rose | Direct sun (at least 4-6 hours) | Deep weekly soak while establishing; little needed once mature | Pet-safe |
| King Alfred Daffodil | Direct sun (at least 4-6 hours) | Moderate during growing season; dry during summer dormancy | Toxic to pets |
| King Billy Pine | Bright indirect light (just back from a sunny window) | Keep consistently moist at all times; never allow to dry out, watering deeply in any dry spell | Mildly toxic to pets |
| King Ferdinand's Saxifrage | Bright indirect light (just back from a sunny window) | Low — water moderately in active growth; reduce sharply in summer dormancy and winter | Pet-safe |
| King George aster | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; rarely needs irrigation in UK climates | Pet-safe |
| King of Hearts Bleeding Heart | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Toxic to pets |
| King of Hearts Brunnera | Low light (north window or shaded room) | Keep soil consistently moist; water when the top 2-3 cm dries, about every 5-7 days in warm weather | Mildly toxic to pets |
| King Size Scarlet everlasting | Direct sun (at least 4-6 hours) | Every 7–10 days; water deeply then let soil partially dry | Pet-safe |
| Kitten Tails | Medium indirect light (a couple of metres from a window) | Infrequently; dry to medium-dry | Mildly toxic to pets |
| Knap Hill Scarlet quince | Bright indirect light (just back from a sunny window) | Weekly when establishing; monthly once established | Mildly toxic to pets |
| Knautia macedonica | Direct sun (at least 4-6 hours) | When the top few centimetres are dry; roughly weekly while establishing | Mildly toxic to pets |
| Kniphofia 'Alcazar' | Direct sun (at least 4-6 hours) | Weekly while establishing and during summer drought; minimal once mature | Pet-safe |
| Kniphofia 'Bees' Sunset' | Direct sun (at least 4-6 hours) | Weekly while establishing and during drought; little once mature | Pet-safe |
| Kniphofia 'Little Maid' | Direct sun (at least 4-6 hours) | Weekly while establishing and in summer drought; sparing once settled | Pet-safe |
| Kniphofia 'Tawny King' | Direct sun (at least 4-6 hours) | Weekly during the first season and in summer drought; established clumps need little once settled | Pet-safe |
| Kniphofia triangularis | Direct sun (at least 4-6 hours) | Every 10-14 days once established, when soil is dry | Pet-safe |
| Kniphofia uvaria | Direct sun (at least 4-6 hours) | Water regularly through the first season, then mainly in summer dry spells once established | Pet-safe |
| Knock Out Rose | Direct sun (at least 4-6 hours) | About 2.5 cm of water weekly, deep soak | Pet-safe |
| Knotted Clover | Direct sun (at least 4-6 hours) | Low; drought-tolerant | Pet-safe |
| Kobus Magnolia | Direct sun (at least 4-6 hours) | Weekly when establishing; once established, natural rainfall is often sufficient except during prolonged drought | Pet-safe |
| Koehne's rowan | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once mature | Mildly toxic to pets |
| Koelreuteria paniculata | Direct sun (at least 4-6 hours) | Weekly for the first 1-2 years; minimal once established | Mildly toxic to pets |
| Kohleria | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, every 5-7 days in growth | Pet-safe |
| Kohleria 'Dark Velvet' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days in growth | Pet-safe |
| Kohleria 'Hannah Roberts' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days in growth | Pet-safe |
| Kohleria amabilis | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days in growth | Pet-safe |
| Kohleria digitaliflora | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Pet-safe |
| Kolkwitzia amabilis | Direct sun (at least 4-6 hours) | Weekly while establishing, then in dry spells | Mildly toxic to pets |
| Kolkwitzia amabilis 'Pink Cloud' | Direct sun (at least 4-6 hours) | Weekly during the first two growing seasons; established plants only in prolonged drought | Mildly toxic to pets |
| Korean Angelica | Medium indirect light (a couple of metres from a window) | 2-3 times per week in active growth; reduce in winter | Mildly toxic to pets |
| Korean Arborvitae | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 1–2 weeks once established | Mildly toxic to pets |
| Korean box | Bright indirect light (just back from a sunny window) | Weekly when young; every 10–14 days once established | Toxic to pets |
| Korean feather reed grass | Bright indirect light (just back from a sunny window) | Water deeply 1-2 times weekly; keep soil consistently moist but not waterlogged | Pet-safe |
| Korean Fir | Direct sun (at least 4-6 hours) | Weekly during establishment; moderately drought-tolerant once mature | Pet-safe |
| Korean Hornbeam | Direct sun (at least 4-6 hours) | When the top 1-2 cm of soil starts to dry, often daily in summer | Mildly toxic to pets |
| Korean Hornbeam Bonsai | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil starts to dry, often daily in summer | Mildly toxic to pets |
| Korean rhododendron | Bright indirect light (just back from a sunny window) | Weekly during establishment and summer; reduce to monthly when dormant | Toxic to pets |
| Korean Spice Viburnum | Direct sun (at least 4-6 hours) | Water when the top 5 cm of soil is dry, about weekly while establishing | Pet-safe |
| Kotschy's Crambe | Bright indirect light (just back from a sunny window) | Moderate — water during dry spells, especially in the establishment year | Mildly toxic to pets |
| Kousa Dogwood | Bright indirect light (just back from a sunny window) | Weekly deep watering while establishing | Pet-safe |
| Krossa Regal Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Kurume Azalea 'Hino Crimson' | Bright indirect light (just back from a sunny window) | About weekly once established, more in heat; water when the top 2-3 cm of soil is dry | Toxic to pets |
| Labrador violet | Medium indirect light (a couple of metres from a window) | Every 5–7 days; keep consistently moist | Pet-safe |
| Laburnum × watereri 'Vossii' | Direct sun (at least 4-6 hours) | Water weekly through the first two seasons, then only in prolonged drought | Toxic to pets |
| Lace Flower Vine | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, about every 5-7 days | Pet-safe |
| Lace-bark Pine | Direct sun (at least 4-6 hours) | Water young trees weekly in dry spells; established trees rarely | Mildly toxic to pets |
| Lacecap Hydrangea | Bright indirect light (just back from a sunny window) | When the top 2-4 cm of soil is dry, often several times a week in heat | Toxic to pets |
| Laced Up Elderberry | Direct sun (at least 4-6 hours) | Weekly for the first 1–2 seasons; every 10–14 days once established | Mildly toxic to pets |
| Lady of Shalott Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season; more in heat or sandy soil | Pet-safe |
| Lady of the Night | Bright indirect light (just back from a sunny window) | When fully dry, roughly every 7-10 days | Pet-safe |
| Lady Slipper Orchid | Bright indirect light (just back from a sunny window) | Every 5-10 days; keep the medium evenly moist | Mildly toxic to pets |
| Lady Tulip | Direct sun (at least 4-6 hours) | Moderate in spring; dry in summer | Toxic to pets |
| Ladybird Scarlet cosmos | Direct sun (at least 4-6 hours) | Weekly; allow soil surface to dry between waterings | Pet-safe |
| Lakeside Black Satin Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil is dry, roughly every 5-7 days during active growth | Toxic to pets |
| Lamance Iris | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; tolerates seasonal flooding of 5–10 cm (2–4 in) for short periods. | Toxic to pets |
| Lamb's Ear | Direct sun (at least 4-6 hours) | Low; water only when soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Lamprocapnos spectabilis 'Alba' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil begins to dry, roughly every 5-7 days in spring | Toxic to pets |
| Lamprocapnos spectabilis 'Gold Heart' | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil begins to dry, roughly every 5-7 days in spring | Toxic to pets |
| Lance-Leaved Trillium | Medium indirect light (a couple of metres from a window) | Moist in spring; more drought-tolerant than most Trilliums once dormant | Mildly toxic to pets |
| Lance-leaved Water Plantain | Direct sun (at least 4-6 hours) | Permanently waterlogged to submerged; 5–30 cm (2–12 in) water depth | Mildly toxic to pets |
| Lanceleaf Coreopsis | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; weekly to establish, then rarely | Pet-safe |
| Lantana | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of soil is dry; roughly weekly in summer, less in cooler weather | Toxic to pets |
| Larch-leaved Sandwort | Direct sun (at least 4-6 hours) | Every 1–2 weeks in summer; minimal in winter | Pet-safe |
| Larch-Leaved Stitchwort | Direct sun (at least 4-6 hours) | Very low — drought-tolerant; water sparingly | Mildly toxic to pets |
| large blue fescue | Direct sun (at least 4-6 hours) | Low to moderate; water every 7–10 days during active growth, monthly once established | Pet-safe |
| Large Masterwort | Medium indirect light (a couple of metres from a window) | Every 5-7 days; soil should remain evenly moist throughout the growing season | Mildly toxic to pets |
| Large Yellow Foxglove | Bright indirect light (just back from a sunny window) | Once or twice a week in dry spells; consistent moisture is important for longevity | Toxic to pets |
| Large-flowered Bacopa | Direct sun (at least 4-6 hours) | Keep soil evenly and consistently moist | Mildly toxic to pets |
| Large-Flowered Beardtongue | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; moderate during first growing season | Mildly toxic to pets |
| Large-flowered Bellwort | Medium indirect light (a couple of metres from a window) | Moderate; water regularly during spring and early summer growth. Established plants tolerate summer drought. | Pet-safe |
| Large-Flowered Houseleek | Direct sun (at least 4-6 hours) | Low — drought-tolerant; water only in prolonged dry periods | Pet-safe |
| Large-Flowered Kohleria | Bright indirect light (just back from a sunny window) | When top 2 in (5 cm) are dry during the growing season; very sparingly in winter dormancy | Pet-safe |
| Large-Flowered Petrocosmea | Medium indirect light (a couple of metres from a window) | Every 7–10 days in growth; sparingly in winter | Pet-safe |
| Large-flowered Rain Lily | Direct sun (at least 4-6 hours) | Allow partial drying between waterings; a dry-wet cycle triggers blooming | Toxic to pets |
| Larkspur | Direct sun (at least 4-6 hours) | Every 5–7 days | Toxic to pets |
| Late Tulip | Direct sun (at least 4-6 hours) | Rainfall-dependent during spring growth; needs dry summer rest | Toxic to pets |
| Laurel-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Every 3–4 weeks once established; weekly in the first season | Mildly toxic to pets |
| Lauren's Grape peony poppy | Direct sun (at least 4-6 hours) | Weekly during establishment; every 10–14 days once plants are growing strongly | Toxic to pets |
| Laurustinus Viburnum | Direct sun (at least 4-6 hours) | Water when the top 5 cm of soil is dry; weekly while establishing, then occasional | Pet-safe |
| Lavaglut Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week, more in heat | Pet-safe |
| Lavender | Direct sun (at least 4-6 hours) | When the top of the soil is dry, every 10-14 days | Toxic to pets |
| Lavender-leaved Sage | Direct sun (at least 4-6 hours) | Every 7–10 days in summer; every 3–4 weeks in winter | Mildly toxic to pets |
| Lawson Cypress | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 2 weeks once established | Mildly toxic to pets |
| Lead Plant | Direct sun (at least 4-6 hours) | Deeply once every 2–3 weeks during the first growing season; essentially no supplemental irrigation once established | Pet-safe |
| Least Primrose | Direct sun (at least 4-6 hours) | Every 7–10 days during active growth; very sparingly in summer and winter | Mildly toxic to pets |
| Least Yellow Pond Lily | Bright indirect light (just back from a sunny window) | Permanently submerged — thrives at water depths of 30–100 cm (1–3 ft). | Mildly toxic to pets |
| Least Yellow Water Lily | Direct sun (at least 4-6 hours) | Permanently aquatic; plant at 20–60 cm (8–24 in) water depth | Mildly toxic to pets |
| Leatherleaf | Bright indirect light (just back from a sunny window) | Consistently wet to moist — never allow to dry out | Toxic to pets |
| Leatherleaf Sedge | Direct sun (at least 4-6 hours) | Water weekly while establishing in year one, then only during prolonged dry spells | Mildly toxic to pets |
| leatherleaf viburnum | Bright indirect light (just back from a sunny window) | Weekly when establishing; every 2–4 weeks once mature | Mildly toxic to pets |
| Lehmann's Iceplant | Direct sun (at least 4-6 hours) | Every 2–3 weeks during spring and summer; monthly or less in winter | Pet-safe |
| Lemboglossum rossii | Bright indirect light (just back from a sunny window) | Water when the bark approaches dryness, roughly every 4-7 days, keeping pseudobulbs plump | Pet-safe |
| Lemmon's marigold | Direct sun (at least 4-6 hours) | Every 7–10 days in summer heat; monthly during cool winter dormancy | Mildly toxic to pets |
| Leopard Plant 'Desdemona' | Medium indirect light (a couple of metres from a window) | Every 3-5 days in warm weather; keep soil consistently moist or wet | Mildly toxic to pets |
| Leopard Plant 'The Rocket' | Medium indirect light (a couple of metres from a window) | Every 3-5 days or more frequently in warm weather; soil should remain consistently moist | Mildly toxic to pets |
| Lesser Periwinkle | Medium indirect light (a couple of metres from a window) | Weekly during establishment; largely self-sufficient in average rainfall climates | Toxic to pets |
| Lesser Pond Sedge | Direct sun (at least 4-6 hours) | Permanently wet; waterlogged soil or up to 20 cm of standing water | Pet-safe |
| Lesser Quaking Grass | Direct sun (at least 4-6 hours) | Water sparingly; keep soil evenly moist during germination and establishment | Pet-safe |
| Lesser Sea Spurrey | Direct sun (at least 4-6 hours) | Low; tolerates periods of drought punctuated by brackish flooding | Mildly toxic to pets |
| Lesser Silver Saxifrage | Direct sun (at least 4-6 hours) | Low — water only when the top layer of grit is dry | Pet-safe |
| Lesser Spearwort | Direct sun (at least 4-6 hours) | Saturated mud to 5 cm standing water | Toxic to pets |
| Lesser Stitchwort | Bright indirect light (just back from a sunny window) | Moderate; keep soil consistently moist but never waterlogged | Mildly toxic to pets |
| Lesser Water Plantain | Direct sun (at least 4-6 hours) | Saturated to 10 cm depth of water | Pet-safe |
| Leucanthemum × superbum 'Alaska' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly weekly; more in extended heat | Toxic to pets |
| Leucanthemum × superbum 'Becky' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly weekly; more in prolonged heat | Toxic to pets |
| Leucanthemum × superbum 'Silver Princess' | Direct sun (at least 4-6 hours) | About once a week, when the top 3-4 cm of soil is dry | Toxic to pets |
| Leucanthemum × superbum 'Snowcap' | Direct sun (at least 4-6 hours) | About once a week, when the top 3-4 cm of soil is dry | Toxic to pets |
| Leucanthemum × superbum 'Wirral Supreme' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about weekly; more during drought | Toxic to pets |
| Leyland Cypress | Direct sun (at least 4-6 hours) | Weekly during the first two years, then only in prolonged drought | Mildly toxic to pets |
| Liatris spicata | Direct sun (at least 4-6 hours) | When the top 3-4 cm is dry; roughly weekly while establishing | Pet-safe |
| Liatris spicata 'Kobold' | Direct sun (at least 4-6 hours) | When the top 3-4 cm is dry; about weekly while establishing | Pet-safe |
| Licorice plant | Bright indirect light (just back from a sunny window) | Every 7–14 days; allow top 2–3 cm to dry | Pet-safe |
| Lifelong Saxifrage | Bright indirect light (just back from a sunny window) | Water moderately; allow the top 2–3 cm of soil to dry before watering. | Pet-safe |
| Lilac 'Charles Joly' | Direct sun (at least 4-6 hours) | Weekly through the first season, then only in drought | Mildly toxic to pets |
| Lilac Sage | Bright indirect light (just back from a sunny window) | Water when the top 5 cm of soil is dry | Pet-safe |
| Lilafee Epimedium | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Mildly toxic to pets |
| Lilium 'Black Beauty' | Direct sun (at least 4-6 hours) | When the top 3-5cm of soil is dry, roughly weekly in the growing season | Toxic to pets |
| Lilium 'Casa Blanca' | Direct sun (at least 4-6 hours) | When the top 3-5cm of soil is dry, about weekly during active growth | Toxic to pets |
| Lilium 'Conca d'Or' | Direct sun (at least 4-6 hours) | When the top 3-5cm of soil is dry, about weekly during growth | Toxic to pets |
| Lilium 'Dizzy' | Direct sun (at least 4-6 hours) | Keep evenly moist in growth, about weekly; never waterlogged | Toxic to pets |
| Lilium 'Matrix' | Direct sun (at least 4-6 hours) | Keep evenly moist through growth and bloom, about weekly; avoid waterlogging | Toxic to pets |
| Lilium 'Regale' | Direct sun (at least 4-6 hours) | When the top 3-5cm of soil is dry, roughly weekly during active growth | Toxic to pets |
| Lilium 'Stargazer' | Direct sun (at least 4-6 hours) | When the top 3-5cm of soil is dry, roughly weekly during growth and flowering | Toxic to pets |
| Lilium 'Tiny Bee' | Direct sun (at least 4-6 hours) | When the top 2-3cm of soil is dry, roughly weekly; more often in pots | Toxic to pets |
| Lilium lancifolium | Direct sun (at least 4-6 hours) | Keep evenly moist in active growth, roughly weekly; never waterlogged | Toxic to pets |
| Lily Magnolia | Bright indirect light (just back from a sunny window) | Weekly during the growing season; reduce in autumn and winter | Pet-safe |
| Lily of the valley | Low light (north window or shaded room) | Weekly watering | Toxic to pets |
| Lime Rickey Heuchera | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, about weekly | Pet-safe |
| Limestone Oak Fern | Bright indirect light (just back from a sunny window) | Keep moist but never waterlogged; water when the top 2 cm dries, roughly weekly in dry spells | Mildly toxic to pets |
| Limestone Saxifrage | Direct sun (at least 4-6 hours) | Low — water sparingly, allow soil to approach dryness between waterings | Pet-safe |
| Linaria maroccana 'Fairy Bouquet' | Direct sun (at least 4-6 hours) | When the top 2 cm of soil is dry, roughly every 4-7 days | Mildly toxic to pets |
| Lindheimer's Muhly | Direct sun (at least 4-6 hours) | Water to establish the first season, then occasionally in drought, roughly every 2-3 weeks | Mildly toxic to pets |
| Lined Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in growth; very sparingly during dormancy | Mildly toxic to pets |
| Lipstick Plant | Bright indirect light (just back from a sunny window) | When the top 2-3 cm is dry, roughly every 7-10 days in growth | Pet-safe |
| Lipstick Plant 'Mona Lisa' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Liquidambar styraciflua | Direct sun (at least 4-6 hours) | Weekly while establishing; keep soil consistently moist | Mildly toxic to pets |
| Liquidambar styraciflua 'Worplesdon' | Direct sun (at least 4-6 hours) | Weekly while establishing; keep soil consistently moist | Mildly toxic to pets |
| Liriodendron tulipifera | Direct sun (at least 4-6 hours) | Deep soak weekly in the first two or three growing seasons, then rely on rainfall | Pet-safe |
| Little Bluestem | Direct sun (at least 4-6 hours) | Every 2–3 weeks during establishment; minimal once established | Pet-safe |
| Little Bunny Fountain Grass | Direct sun (at least 4-6 hours) | Weekly while establishing in the first season, then only during prolonged drought | Pet-safe |
| Little Gem Magnolia | Direct sun (at least 4-6 hours) | Weekly while establishing (1–3 years); deep watering in summer drought thereafter | Pet-safe |
| Little Gem Spruce | Direct sun (at least 4-6 hours) | Every 5-7 days; keep the small root zone evenly moist, watering when the surface dries | Pet-safe |
| Little Heath pieris | Bright indirect light (just back from a sunny window) | Weekly; maintain consistent moisture | Toxic to pets |
| Little Kitten Dwarf Maiden Grass | Direct sun (at least 4-6 hours) | Weekly to establish, then during dry spells; container plants need more frequent water | Mildly toxic to pets |
| little silver spider grass | Direct sun (at least 4-6 hours) | Every 7–10 days during the growing season; reduce significantly in winter | Pet-safe |
| Little Sweet Betsy | Medium indirect light (a couple of metres from a window) | Consistently moist from emergence through early summer; reduced in summer dormancy | Mildly toxic to pets |
| Lobb's Bulbophyllum | Medium indirect light (a couple of metres from a window) | Keep evenly moist in growth; water every 3-5 days | Pet-safe |
| Lobbi Japanese Cedar | Direct sun (at least 4-6 hours) | Weekly during establishment; fortnightly in dry spells once mature | Mildly toxic to pets |
| Lobed Tickseed | Bright indirect light (just back from a sunny window) | Low to moderate; drought-tolerant but benefits from occasional watering | Pet-safe |
| Lobelia cardinalis | Direct sun (at least 4-6 hours) | Keep consistently moist to wet; never let it dry out | Toxic to pets |
| Lobelia erinus 'Cascade Blue' | Direct sun (at least 4-6 hours) | Keep consistently moist; check baskets daily in warm weather | Toxic to pets |
| Lobelia erinus 'Riviera Lilac' | Direct sun (at least 4-6 hours) | Keep evenly moist; water when the surface starts to dry | Toxic to pets |
| Lobelia erinus 'Techno Heat Blue' | Direct sun (at least 4-6 hours) | Keep consistently moist; check baskets daily in hot weather | Toxic to pets |
| Lobelia siphilitica | Direct sun (at least 4-6 hours) | Keep consistently moist; tolerates wet soil and short dry spells | Toxic to pets |
| Lobivia famatimensis | Direct sun (at least 4-6 hours) | Water thoroughly when the mix dries out, roughly every 1-2 weeks in summer; keep dry through winter | Pet-safe |
| Loblolly Pine Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm is dry, commonly daily in summer and every 3-5 days in cool weather | Pet-safe |
| Lobster Flower | Bright indirect light (just back from a sunny window) | Every 2–3 weeks in summer; monthly or less in winter | Pet-safe |
| London Pride | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season; less in winter | Pet-safe |
| London Pride | Medium indirect light (a couple of metres from a window) | Weekly during dry spells; little additional watering needed in temperate climates | Pet-safe |
| Lonesome Dove Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil is dry, about every 5-7 days during active growth | Toxic to pets |
| Long-Beaked Stork's Bill | Direct sun (at least 4-6 hours) | Water lightly during the cooler growing season; minimal water needed in summer | Mildly toxic to pets |
| Long-flowered Sage | Direct sun (at least 4-6 hours) | Every 10–14 days in summer; rarely in winter | Mildly toxic to pets |
| Long-leaved Pelargonium | Direct sun (at least 4-6 hours) | Water moderately during active growth (autumn–spring); withhold almost entirely in summer dormancy | Toxic to pets |
| Long-Leaved Phlomis | Direct sun (at least 4-6 hours) | Low — water every 2–3 weeks during the growing season; minimal to none in winter | Mildly toxic to pets |
| Long-leaved speedwell | Direct sun (at least 4-6 hours) | Weekly during the growing season; reduce in winter | Pet-safe |
| Long-lipped Tongue Orchid | Direct sun (at least 4-6 hours) | Winter-wet, summer-dry cycle; water lightly in autumn through spring, withhold completely in summer | Mildly toxic to pets |
| Long-Petalled Lewisia | Bright indirect light (just back from a sunny window) | Moderate in spring; almost dry in summer dormancy | Mildly toxic to pets |
| Long-Spurred Violet | Medium indirect light (a couple of metres from a window) | Regular; keep soil evenly moist | Pet-safe |
| Long-Stalked Cranesbill | Direct sun (at least 4-6 hours) | Low; tolerates extended dry periods | Pet-safe |
| Long-stalked Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in growth; reduce slightly during rest period | Mildly toxic to pets |
| Long-stalked Spiderwort | Medium indirect light (a couple of metres from a window) | Weekly during active growth; reduce after summer die-back | Mildly toxic to pets |
| Long-stamen Sage | Direct sun (at least 4-6 hours) | Every 10–14 days once established | Pet-safe |
| Long-stamened Sage | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries out, roughly every 5-8 days in summer | Pet-safe |
| Long-styled Sage | Direct sun (at least 4-6 hours) | Every 10–14 days in summer; very sparingly in winter | Mildly toxic to pets |
| Longcluster Japanese Wisteria | Direct sun (at least 4-6 hours) | Every 7–14 days during dry periods; established plants need little supplemental watering | Toxic to pets |
| Longleaf Phlox | Direct sun (at least 4-6 hours) | Every 14–21 days when establishing; minimal supplemental water once established | Pet-safe |
| Lonicera caprifolium | Direct sun (at least 4-6 hours) | Keep the root zone evenly moist; water deeply in dry spells, every 5-7 days in summer heat | Mildly toxic to pets |
| Lonicera japonica | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, around every 5-10 days while establishing | Mildly toxic to pets |
| Lonicera periclymenum | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil dries, roughly every 5-10 days while establishing | Mildly toxic to pets |
| Lonicera periclymenum 'Serotina' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil dries, roughly every 5-10 days while establishing | Mildly toxic to pets |
| Lonicera sempervirens | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries, about every 5-10 days while establishing | Mildly toxic to pets |
| Lonicera x heckrottii | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries, about every 5-10 days while establishing | Mildly toxic to pets |
| Lords-and-Ladies | Low light (north window or shaded room) | Weekly during active growth (autumn–spring); reduce in summer dormancy | Toxic to pets |
| Love-in-a-mist | Direct sun (at least 4-6 hours) | Once or twice a week; established plants rarely need supplemental watering in cool, moist climates | Toxic to pets |
| Love-lies-bleeding | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Loving Touch Miniature Rose | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 2-4 days in summer | Pet-safe |
| Loxostigma griffithii | Medium indirect light (a couple of metres from a window) | When the surface begins to dry, roughly every 4-6 days in growth | Mildly toxic to pets |
| Lungwort | Medium indirect light (a couple of metres from a window) | Twice weekly in dry spells; keep soil consistently moist | Mildly toxic to pets |
| Lungwort 'Bertram Anderson' | Medium indirect light (a couple of metres from a window) | Every 7-10 days; somewhat more drought-tolerant than other pulmonarias but still prefers consistent moisture | Pet-safe |
| Lungwort 'Mrs Moon' | Medium indirect light (a couple of metres from a window) | Every 5-7 days in the growing season; keep soil moist but not waterlogged | Pet-safe |
| Lungwort Pulmonaria | Low light (north window or shaded room) | Keep soil evenly moist; water every 4-6 days in dry spells, more in containers | Mildly toxic to pets |
| Lupin 'The Governor' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Lupine | Direct sun (at least 4-6 hours) | Weekly watering | Toxic to pets |
| Lupinus 'Chandelier' | Direct sun (at least 4-6 hours) | Every 5-7 days; keep the soil evenly moist, never sodden | Toxic to pets |
| Lupinus 'Manhattan Lights' | Direct sun (at least 4-6 hours) | Every 5-7 days; keep soil consistently moist but well-drained | Toxic to pets |
| Lupinus 'Masterpiece' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply once or twice weekly in dry spells | Toxic to pets |
| Lupinus 'Tequila Flame' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; deep water once or twice weekly when dry | Toxic to pets |
| Lupinus 'The Governor' | Direct sun (at least 4-6 hours) | Every 5-7 days; keep soil consistently moist, never waterlogged | Toxic to pets |
| Lupinus polyphyllus 'Gallery Blue' | Direct sun (at least 4-6 hours) | Every 5-7 days; maintain evenly moist soil without waterlogging | Toxic to pets |
| Luxuriant Bleeding Heart | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Toxic to pets |
| Lycaste aromatica | Bright indirect light (just back from a sunny window) | Every 4-6 days while in leaf; sparingly once leaves drop | Pet-safe |
| Lycaste skinneri | Bright indirect light (just back from a sunny window) | Every 5-7 days in active growth; reduce sharply after leaf drop, roughly every 2-3 weeks in winter rest | Pet-safe |
| Lycian Sage Phlomis | Direct sun (at least 4-6 hours) | Low — every 2–3 weeks in the growing season; minimal to none in winter | Mildly toxic to pets |
| Lydian Broom | Direct sun (at least 4-6 hours) | Low — drought-tolerant; water only to establish | Toxic to pets |
| Lydian Stonecrop | Direct sun (at least 4-6 hours) | Every 2–3 weeks in summer; monthly or less in winter | Pet-safe |
| Lysimachia nummularia | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water whenever the surface begins to dry | Mildly toxic to pets |
| Lysimachia nummularia 'Aurea' | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water whenever the surface starts to dry | Mildly toxic to pets |
| Lythrum salicaria | Direct sun (at least 4-6 hours) | Keep wet; thrives in saturated soil and shallow water | Mildly toxic to pets |
| Mackay's Heath | Direct sun (at least 4-6 hours) | Regular; keep soil consistently moist | Mildly toxic to pets |
| Mackay's Zygopetalum | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is nearly dry, roughly every 5-7 days | Pet-safe |
| Madagascar Jasmine | Bright indirect light (just back from a sunny window) | When the top 2-3cm of soil starts to dry (spring-summer); sparingly in winter | Pet-safe |
| Madagascar Periwinkle (Vinca) | Direct sun (at least 4-6 hours) | When the top 2-3 cm (1 in) of soil is dry, roughly weekly | Toxic to pets |
| Madame Alfred Carriere Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly when establishing; mature plants when the top few centimetres of soil dry, and they tolerate some drought | Pet-safe |
| Madame Butterfly snapdragon | Direct sun (at least 4-6 hours) | Every 5–7 days; keep evenly moist | Pet-safe |
| Madame Galen Trumpet Vine | Direct sun (at least 4-6 hours) | Weekly when young; drought-tolerant once established | Mildly toxic to pets |
| Madame Lemoine Lilac | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days; established plants are drought-tolerant | Pet-safe |
| Madonna Lily | Direct sun (at least 4-6 hours) | Moderate; water during active growth, reduce as dormancy approaches | Toxic to pets |
| Madonna White Snapdragon | Direct sun (at least 4-6 hours) | When the top 2–3 cm of soil is dry, roughly every 5–7 days | Pet-safe |
| Magnificent Inula | Bright indirect light (just back from a sunny window) | 2-3 times per week; tolerates moist to wet conditions | Pet-safe |
| Magnificent Juno Iris | Direct sun (at least 4-6 hours) | Moderate in growth; dry in summer dormancy | Toxic to pets |
| Magnolia 'Elizabeth' | Direct sun (at least 4-6 hours) | Weekly during the first few years and in summer droughts | Pet-safe |
| Magnolia 'Jane' | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the first two years, then during dry spells | Pet-safe |
| Magnolia 'Susan' | Direct sun (at least 4-6 hours) | Keep moist while establishing; water deeply weekly in dry spells for the first few years | Pet-safe |
| Magnolia grandiflora 'Gallissonnière' | Direct sun (at least 4-6 hours) | Weekly deep watering in the first 2-3 years, then only during prolonged dry spells | Pet-safe |
| Magnolia wilsonii | Bright indirect light (just back from a sunny window) | Weekly while establishing and during dry summer spells | Pet-safe |
| Magnolia-leaved Sage | Bright indirect light (just back from a sunny window) | Weekly in summer; every 2–3 weeks in winter | Mildly toxic to pets |
| Mahonia aquifolium Apollo | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, weekly through the first year then occasionally | Pet-safe |
| Mahonia Charity | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, weekly to establish then chiefly during droughts | Pet-safe |
| Mahonia Pinnacle | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, weekly through the first year then occasionally | Pet-safe |
| Mahonia repens | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, weekly to establish then rarely | Pet-safe |
| Mahonia Soft Caress | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, about weekly and more attentively than spinier mahonias | Pet-safe |
| Mahonia Winter Sun | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, weekly while establishing then only in dry spells | Pet-safe |
| Maiden Grass | Direct sun (at least 4-6 hours) | Weekly during the first growing season; every 2–3 weeks once established | Pet-safe |
| Maidenhair Tree | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil dries, roughly every 1-3 days in summer | Mildly toxic to pets |
| Maire's fescue | Direct sun (at least 4-6 hours) | Low; water every 2–3 weeks during dry spells; once established, relies on natural rainfall in most temperate climates | Pet-safe |
| Majeste Pulmonaria | Low light (north window or shaded room) | Keep soil evenly moist; water every 4-6 days in dry weather, more for containers | Mildly toxic to pets |
| Majestic Giants Pansy | Bright indirect light (just back from a sunny window) | When the top 1–2 cm of soil starts to dry, roughly every 3–5 days in mild weather | Mildly toxic to pets |
| Maleberry | Bright indirect light (just back from a sunny window) | Regular to frequent; prefers moist to wet conditions | Toxic to pets |
| Malepartus silver grass | Direct sun (at least 4-6 hours) | Weekly during the growing season; reduce in autumn; minimal in winter | Pet-safe |
| Maltese cross | Direct sun (at least 4-6 hours) | Every 5–7 days in the growing season; less in cool or wet periods | Pet-safe |
| Malus 'Profusion' | Direct sun (at least 4-6 hours) | Water regularly while establishing; mature trees need water only in prolonged drought | Toxic to pets |
| Malus 'Royalty' | Direct sun (at least 4-6 hours) | Water regularly for the first 2-3 years; established trees need water only in extended drought | Toxic to pets |
| Malus floribunda | Direct sun (at least 4-6 hours) | Water regularly during establishment; mature trees need water only in extended drought | Toxic to pets |
| Malus tschonoskii | Direct sun (at least 4-6 hours) | Water regularly for the first 2-3 years; established trees need water only in prolonged drought | Toxic to pets |
| Mandevilla 'Alice du Pont' | Direct sun (at least 4-6 hours) | Keep evenly moist in summer; water when the top 2-3 cm of soil dries, often every 2-4 days in heat | Mildly toxic to pets |
| Manhattan Euonymus | Bright indirect light (just back from a sunny window) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| Manna Ash | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Pet-safe |
| Many-Coloured Zygopetalum | Bright indirect light (just back from a sunny window) | When the surface is approaching dry, roughly every 4-6 days; more often if mounted | Pet-safe |
| many-flowered cape primrose | Medium indirect light (a couple of metres from a window) | Every 10–14 days; allow soil to dry between waterings | Pet-safe |
| Many-Flowered Cornflag | Direct sun (at least 4-6 hours) | Weekly during autumn-to-spring growing season; dry in summer dormancy | Mildly toxic to pets |
| Many-flowered Heath | Direct sun (at least 4-6 hours) | Moderate to infrequent; drought-tolerant once established | Mildly toxic to pets |
| Many-Flowered Ruschia | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season (autumn–spring); very sparingly in summer | Mildly toxic to pets |
| Many-Flowered Rush | Direct sun (at least 4-6 hours) | Frequent to constant — prefers permanently moist to wet soil | Pet-safe |
| Many-haired Draba | Direct sun (at least 4-6 hours) | Every 10–14 days during growth; almost dry in winter | Pet-safe |
| Many-spiked Ixia | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry during active growth, roughly every 10-14 days | Toxic to pets |
| Many-spiked Sage | Direct sun (at least 4-6 hours) | Moderate; water when the top 5 cm of soil is dry | Mildly toxic to pets |
| Marginal Wood Fern | Low light (north window or shaded room) | Keep evenly moist while establishing; water deeply during droughts, about every 7-10 days in dry summers | Pet-safe |
| Marginata Wood Rush | Medium indirect light (a couple of metres from a window) | Low to moderate; water during dry spells in the first growing season, then minimal supplemental water needed | Pet-safe |
| Margined Saxifrage | Bright indirect light (just back from a sunny window) | Every 7–10 days when growing; very sparingly in winter | Pet-safe |
| Marie Simon Ceanothus | Direct sun (at least 4-6 hours) | Every 7-10 days in the growing season, allowing the top few centimetres of soil to dry between waterings; less in winter | Mildly toxic to pets |
| Maries Doublefile Viburnum | Bright indirect light (just back from a sunny window) | When the top 5 cm of soil is dry, roughly every 7–10 days; more frequently during establishment and dry spells | Mildly toxic to pets |
| Marigold | Direct sun (at least 4-6 hours) | When the top of the soil is dry, every 5-7 days | Mildly toxic to pets |
| Marmalade Heuchera | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Pet-safe |
| Marseille Germander | Direct sun (at least 4-6 hours) | Infrequently once established; weekly when newly planted | Mildly toxic to pets |
| Marsh Afrikaner | Direct sun (at least 4-6 hours) | Moderate during winter–spring growing season; withhold entirely once foliage dies back in summer | Toxic to pets |
| Marsh Fern | Bright indirect light (just back from a sunny window) | Keep wet to saturated at all times; never allow the soil to dry out | Mildly toxic to pets |
| Martagon Lily | Medium indirect light (a couple of metres from a window) | When top 3–4 cm of soil feels dry | Toxic to pets |
| Martinezii Lily | Direct sun (at least 4-6 hours) | Dry in summer; moderate in winter-to-spring growth period | Toxic to pets |
| Masked Twinspur | Bright indirect light (just back from a sunny window) | Water regularly to keep soil evenly moist | Mildly toxic to pets |
| Masters' Larch | Direct sun (at least 4-6 hours) | Weekly during first 2 years; monthly once established | Pet-safe |
| Masterwort 'Ruby Wedding' | Medium indirect light (a couple of metres from a window) | Every 5-7 days in warm weather; reduce in cooler months when growth slows | Mildly toxic to pets |
| Masterwort 'Venice' | Medium indirect light (a couple of metres from a window) | Every 5-7 days; do not allow soil to dry out during active growth | Mildly toxic to pets |
| Mathilde's Rock Jasmine | Direct sun (at least 4-6 hours) | Sparingly; allow to nearly dry between waterings | Mildly toxic to pets |
| Matsumoto Mix aster | Direct sun (at least 4-6 hours) | 2–3 times per week in warm weather; reduce in cool or overcast periods | Pet-safe |
| Matted Globularia | Direct sun (at least 4-6 hours) | Every 10–14 days in summer; minimal in winter — avoid wetting the crown. | Mildly toxic to pets |
| Matted Sea Lavender | Direct sun (at least 4-6 hours) | Every 2–3 weeks; very sparingly in winter | Pet-safe |
| Matthiola incana 'Giant Imperial Mix' | Direct sun (at least 4-6 hours) | Keep evenly moist; water every 3-5 days, adjusting to weather | Pet-safe |
| Matthiola incana 'Katz Sakura' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water every 3-5 days, more in heat | Pet-safe |
| Maudiae Slipper Orchid | Medium indirect light (a couple of metres from a window) | When the top of the mix begins to dry, roughly every 5-7 days | Pet-safe |
| Maudiae-Type Slipper 'Black Jack' | Medium indirect light (a couple of metres from a window) | When the top of the mix is just starting to dry, roughly every 5-7 days | Mildly toxic to pets |
| Maxillaria tenuifolia | Bright indirect light (just back from a sunny window) | When the medium is approaching dryness, roughly every 4-6 days in growth | Pet-safe |
| Maxillaria variabilis | Bright indirect light (just back from a sunny window) | When the medium nears dryness, about every 4-6 days in growth | Pet-safe |
| Maximilian Sunflower | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; minimal supplemental irrigation needed | Pet-safe |
| May Night Salvia | Direct sun (at least 4-6 hours) | When top 3-5 cm of soil is dry, roughly every 7-10 days once established | Pet-safe |
| Mayapple | Low light (north window or shaded room) | 1–2 times per week during spring; reduce as plant enters summer dormancy | Toxic to pets |
| Meadow Blazing Star | Direct sun (at least 4-6 hours) | Keep evenly moist to medium; water during dry spells | Pet-safe |
| Meadow Buttercup | Direct sun (at least 4-6 hours) | Naturally thrives in moist conditions; water weekly in dry spells | Toxic to pets |
| Meadow Clary | Direct sun (at least 4-6 hours) | Low to moderate; water when the top 5 cm is dry | Mildly toxic to pets |
| meadow fountain grass | Direct sun (at least 4-6 hours) | Weekly when new; every 2–3 weeks once established | Pet-safe |
| Meadow Oat Grass | Direct sun (at least 4-6 hours) | Low; very drought-tolerant | Pet-safe |
| Meadow Phlox | Direct sun (at least 4-6 hours) | 1-2 times per week; prefers consistently moist soil | Mildly toxic to pets |
| Meadow Saxifrage | Bright indirect light (just back from a sunny window) | Every 5–7 days in spring; minimal watering needed from midsummer onward | Pet-safe |
| Meadow Vetchling | Bright indirect light (just back from a sunny window) | Moderate — keep consistently moist but well-drained | Mildly toxic to pets |
| Mealy-cup Sage | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days when young; every 10-14 days once established | Pet-safe |
| Mealycup Sage 'Victoria Blue' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; roughly weekly, less once established | Pet-safe |
| Mediterranean Everlasting | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established | Mildly toxic to pets |
| Mediterranean feather grass | Direct sun (at least 4-6 hours) | Every 3–4 weeks once established; minimal in winter | Pet-safe |
| Mediterranean Sea Holly | Direct sun (at least 4-6 hours) | Low — water young plants to establish, then rely on rainfall | Pet-safe |
| Medusa Orchid | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water every 2-4 days, more in heat | Pet-safe |
| Melancholy Thistle | Bright indirect light (just back from a sunny window) | Moderate — keep soil moist | Mildly toxic to pets |
| Menyanthes trifoliata | Direct sun (at least 4-6 hours) | Keep permanently in wet mud or shallow water; never let it dry | Mildly toxic to pets |
| Mexican Bush Sage | Direct sun (at least 4-6 hours) | Every 7–10 days in summer; every 2–3 weeks in autumn | Mildly toxic to pets |
| Mexican Cypress | Direct sun (at least 4-6 hours) | Weekly during establishment; fortnightly in dry periods once mature | Mildly toxic to pets |
| Mexican Feather Grass | Direct sun (at least 4-6 hours) | Water to establish, then only in prolonged drought | Mildly toxic to pets |
| Mexican Fleabane | Direct sun (at least 4-6 hours) | Every 10–14 days during active growth; minimal once established | Pet-safe |
| Mexican Hat | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; very drought-tolerant | Pet-safe |
| Mexican Lily | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry during active growth, roughly every 7-10 days | Toxic to pets |
| Mexican Orange Sage | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries out, roughly every 5-8 days during the growing season | Pet-safe |
| Mexican Sage | Direct sun (at least 4-6 hours) | Weekly during active growth | Pet-safe |
| Mexican sunflower | Direct sun (at least 4-6 hours) | Weekly until established; then every 10–14 days; drought-tolerant once mature | Mildly toxic to pets |
| Mexican zinnia | Direct sun (at least 4-6 hours) | Once or twice weekly; allow the top 2–3 cm of soil to dry between waterings | Pet-safe |
| Meyer's Cape Primrose | Bright indirect light (just back from a sunny window) | Every 10-14 days in growth; every 4-6 weeks in winter | Pet-safe |
| Michaelovsky Fritillary | Direct sun (at least 4-6 hours) | Moderate during active growth in spring; withhold almost completely from midsummer through autumn | Toxic to pets |
| Midas Touch Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly during growth | Pet-safe |
| Middendorf Weigela | Bright indirect light (just back from a sunny window) | Every 7 days during dry periods; keep evenly moist but not waterlogged | Pet-safe |
| Mignonette | Direct sun (at least 4-6 hours) | Every 5–7 days; do not allow to dry out completely | Pet-safe |
| Mignonette Peperomia | Bright indirect light (just back from a sunny window) | Every 10–14 days in the growing season; every 2–3 weeks in winter | Pet-safe |
| Milkflower cotoneaster | Direct sun (at least 4-6 hours) | Weekly during the first growing season; drought-tolerant once established | Mildly toxic to pets |
| Milky bellflower | Direct sun (at least 4-6 hours) | Weekly during dry periods; moderate water requirements | Pet-safe |
| Milky Bellflower 'Prichard's Variety' | Bright indirect light (just back from a sunny window) | Once or twice a week in dry spells; regular moisture during flowering improves performance | Mildly toxic to pets |
| Milky Way Kousa Dogwood | Bright indirect light (just back from a sunny window) | Weekly while establishing; deep watering in summer drought | Pet-safe |
| Million bells | Direct sun (at least 4-6 hours) | Daily in hot weather for containers; every 2–3 days in cooler periods | Mildly toxic to pets |
| Million Bells 'Superbells' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry — let it dry slightly between waterings | Pet-safe |
| Miltonia Orchid | Bright indirect light (just back from a sunny window) | Every 2-5 days in active growth; let medium approach dryness, never bone-dry | Pet-safe |
| Miltoniopsis 'Augres' | Medium indirect light (a couple of metres from a window) | Keep evenly moist; usually every 4-6 days | Pet-safe |
| Miltoniopsis 'Herralexandre' | Medium indirect light (a couple of metres from a window) | When the mix surface starts to dry, roughly every 4-6 days | Pet-safe |
| Miltoniopsis 'Red Tide' | Medium indirect light (a couple of metres from a window) | Keep the mix evenly moist; typically every 4-6 days | Pet-safe |
| Miltoniopsis phalaenopsis | Medium indirect light (a couple of metres from a window) | Every 3-5 days, keeping the mix lightly moist at all times | Pet-safe |
| Miltoniopsis roezlii | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water every 3-5 days, never letting the mix fully dry | Pet-safe |
| Mimulus ringens | Direct sun (at least 4-6 hours) | Keep wet at all times; never allow the soil to dry | Mildly toxic to pets |
| Min Fir | Direct sun (at least 4-6 hours) | Regularly during establishment; moderate thereafter | Pet-safe |
| Mini Moth Orchid 'Sogo Vivien' | Bright indirect light (just back from a sunny window) | Roughly every 7-10 days, when the bark mix is nearly dry and roots turn silvery-grey | Pet-safe |
| Miniature Creeping Jenny | Medium indirect light (a couple of metres from a window) | Frequently; keep soil consistently moist | Mildly toxic to pets |
| Miniature Sinningia | Bright indirect light (just back from a sunny window) | Keep evenly, lightly moist at all times; check every few days | Pet-safe |
| Minnesota Trout Lily | Medium indirect light (a couple of metres from a window) | Moist throughout active growth (April–May); bone-dry conditions are fatal | Mildly toxic to pets |
| Minuteman Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil is dry, about every 5-7 days in the growing season | Toxic to pets |
| Miss Grace Dawn Redwood | Direct sun (at least 4-6 hours) | Weekly or more in dry periods; tolerates wet soils | Pet-safe |
| Miss Jekyll love-in-a-mist | Direct sun (at least 4-6 hours) | Weekly or as needed | Mildly toxic to pets |
| Miss Kim Lilac | Direct sun (at least 4-6 hours) | Weekly to establish, then occasional deep watering in drought | Mildly toxic to pets |
| Miss Willmott's Ghost | Direct sun (at least 4-6 hours) | Low — once established, water only during prolonged drought | Pet-safe |
| Miss Wilmott's Ghost | Direct sun (at least 4-6 hours) | Water occasionally in the first year, then rarely once established | Mildly toxic to pets |
| Missouri Coneflower | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; very drought-tolerant | Mildly toxic to pets |
| Missouri Ironweed | Direct sun (at least 4-6 hours) | Moderate to high — prefers moist soil | Mildly toxic to pets |
| Mister Lincoln Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Mock Orange | Direct sun (at least 4-6 hours) | Water in dry spells; drought-tolerant once established | Mildly toxic to pets |
| Mock Orange 'Belle Etoile' | Direct sun (at least 4-6 hours) | Weekly while establishing; during dry spells thereafter | Mildly toxic to pets |
| Modest Cape Primrose | Medium indirect light (a couple of metres from a window) | Every 7-10 days in growth; every 3-4 weeks in winter | Pet-safe |
| Modoc Cypress | Direct sun (at least 4-6 hours) | Minimal once established; drought-tolerant | Pet-safe |
| Momi Fir | Direct sun (at least 4-6 hours) | Moderate; water regularly during establishment | Pet-safe |
| Monarch Birch | Direct sun (at least 4-6 hours) | Regular watering for first 2–3 years; moderate once established | Pet-safe |
| Monarch of the Veldt | Direct sun (at least 4-6 hours) | Every 10–14 days once established | Mildly toxic to pets |
| Monarda 'Jacob Cline' | Direct sun (at least 4-6 hours) | Water deeply about once or twice a week, keeping soil consistently moist | Mildly toxic to pets |
| Monarda 'Marshall's Delight' | Direct sun (at least 4-6 hours) | Water deeply once or twice a week to keep soil evenly moist | Mildly toxic to pets |
| Mongolian Linden | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 2 weeks in dry summers | Pet-safe |
| Monkey flower | Medium indirect light (a couple of metres from a window) | Every 2–3 days; more frequently in warm or windy weather | Pet-safe |
| Monkeyflower | Bright indirect light (just back from a sunny window) | Constantly moist to wet — water daily in dry spells | Mildly toxic to pets |
| Mont Cenis Bellflower | Direct sun (at least 4-6 hours) | Very low — water sparingly during growth; keep dry in winter | Mildly toxic to pets |
| Montbretia 'Lucifer' | Direct sun (at least 4-6 hours) | Approximately every 7-10 days during the growing season; reduce to monthly once dormant in autumn | Mildly toxic to pets |
| Monterey Cypress | Direct sun (at least 4-6 hours) | Weekly during establishment; infrequent once mature | Mildly toxic to pets |
| Montezuma Cypress | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water deeply every 7-14 days, more frequently in heat | Pet-safe |
| Montgomery Astilbe | Bright indirect light (just back from a sunny window) | Keep soil consistently moist to wet; water when the top 2-3 cm dries, roughly every 3-5 days in summer | Mildly toxic to pets |
| Montpellier Rock Rose | Direct sun (at least 4-6 hours) | Low — establishment watering only | Mildly toxic to pets |
| Moonflower | Direct sun (at least 4-6 hours) | Weekly, more often in hot or dry spells | Toxic to pets |
| Moonglow Juniper | Direct sun (at least 4-6 hours) | Every 7-10 days when establishing, then deep occasional soaks | Mildly toxic to pets |
| Moonshadow Euonymus | Bright indirect light (just back from a sunny window) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| Moor Witch Purple Moor Grass | Bright indirect light (just back from a sunny window) | Moderate to frequent — prefers reliably moist soil; dislikes drought | Pet-safe |
| Moorcroft's Sage | Direct sun (at least 4-6 hours) | Moderate during growth; minimal in winter | Pet-safe |
| Moore's Crinum | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days in the growing season | Toxic to pets |
| Mophead Hydrangea 'Cityline Paris' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, often 2-3 times weekly in summer heat | Toxic to pets |
| Moretti's Bellflower | Bright indirect light (just back from a sunny window) | Low to moderate — water carefully during growth, keep dry in winter | Mildly toxic to pets |
| Morning Light Maiden Grass | Direct sun (at least 4-6 hours) | Weekly while establishing in the first year, then only during prolonged drought | Mildly toxic to pets |
| Morning Light Maiden Grass | Direct sun (at least 4-6 hours) | Weekly for the first growing season; every 2–3 weeks once established | Pet-safe |
| Moroccan Sea Holly | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established, water sparingly in winter | Pet-safe |
| Moroccan toadflax | Direct sun (at least 4-6 hours) | Once or twice a week; reduce to weekly once established | Mildly toxic to pets |
| Mosquito Plant | Direct sun (at least 4-6 hours) | Every 7–14 days once established; more frequent when young | Pet-safe |
| Moss Campion | Direct sun (at least 4-6 hours) | Sparingly in summer; almost none in winter | Pet-safe |
| Moss Phlox | Direct sun (at least 4-6 hours) | Moderate — water during establishment and dry spells | Pet-safe |
| Moss rose | Direct sun (at least 4-6 hours) | When the soil is thoroughly dry, roughly every 7-10 days in summer | Toxic to pets |
| Mossy cassiope | Bright indirect light (just back from a sunny window) | Consistently moist; never allow soil to dry out | Pet-safe |
| Mossy Saxifrage | Bright indirect light (just back from a sunny window) | Every 5–7 days during active growth; reduce in summer heat and winter | Pet-safe |
| Moth Mullein | Direct sun (at least 4-6 hours) | Every 10–14 days during dry spells; largely self-sufficient once established | Mildly toxic to pets |
| Moth orchid | Bright indirect light (just back from a sunny window) | Roughly weekly; let the bark approach dryness first | Pet-safe |
| Moth Orchid | Bright indirect light (just back from a sunny window) | When the bark mix is nearly dry, typically every 7-10 days | Pet-safe |
| Mother of Pearl poppy | Direct sun (at least 4-6 hours) | Once or twice weekly during establishment; minimal once established | Mildly toxic to pets |
| Mottled Wild Ginger | Low light (north window or shaded room) | Every 7–10 days during the growing season; every 14 days once well established | Mildly toxic to pets |
| Moudry Black Fountain Grass | Direct sun (at least 4-6 hours) | Weekly during establishment, then occasional deep watering in dry spells | Pet-safe |
| Mount Etna Broom | Direct sun (at least 4-6 hours) | Low — very drought-tolerant once established | Toxic to pets |
| Mountain African Daisy | Direct sun (at least 4-6 hours) | Every 7–10 days during the growing season | Mildly toxic to pets |
| Mountain Alyssum | Direct sun (at least 4-6 hours) | Every 14–21 days during growth; minimal in winter | Pet-safe |
| Mountain Bellwort | Medium indirect light (a couple of metres from a window) | Once per week during the growing season; less frequent than other bellworts owing to this species' preference for drier conditions. | Mildly toxic to pets |
| Mountain Bluebells | Bright indirect light (just back from a sunny window) | Water deeply 2–3 times per week; does not tolerate drying out | Pet-safe |
| Mountain Cornflower | Direct sun (at least 4-6 hours) | Weekly in the first season; established plants are drought-tolerant and rarely need watering | Pet-safe |
| Mountain Desert Sage | Direct sun (at least 4-6 hours) | Very low once established; xeric to moderate | Pet-safe |
| Mountain Everlasting | Direct sun (at least 4-6 hours) | Every 2–3 weeks during growing season; minimal in winter | Pet-safe |
| Mountain Fern | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water when the top 2-3 cm dry out, roughly weekly in dry weather | Mildly toxic to pets |
| Mountain Fetterbush | Bright indirect light (just back from a sunny window) | Water every 7–14 days; once established it is relatively drought-tolerant for a Pieris | Toxic to pets |
| Mountain Fire pieris | Bright indirect light (just back from a sunny window) | Weekly to bi-weekly depending on conditions | Toxic to pets |
| Mountain Germander | Direct sun (at least 4-6 hours) | Rarely once established; water during dry spells in the first season | Mildly toxic to pets |
| Mountain Hemlock | Direct sun (at least 4-6 hours) | Weekly during establishment; relies on rainfall and snowmelt once established | Pet-safe |
| Mountain Hydrangea 'Bluebird' | Bright indirect light (just back from a sunny window) | About weekly, roughly 2.5 cm (1 inch) per week; water when the top 3-5 cm of soil is dry | Toxic to pets |
| mountain laurel | Bright indirect light (just back from a sunny window) | Weekly during establishment; water during dry spells once established | Toxic to pets |
| Mountain Laurel 'Olympic Fire' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry; keep evenly moist, especially in the first years | Toxic to pets |
| Mountain Pansy | Bright indirect light (just back from a sunny window) | Water sparingly; allow soil to partially dry between waterings. | Pet-safe |
| Mountain Phlox | Medium indirect light (a couple of metres from a window) | Weekly; allow the top 2–3 cm of soil to dry between waterings | Pet-safe |
| Mountain Pieris | Bright indirect light (just back from a sunny window) | Keep evenly moist; water weekly in dry weather and never allow drought stress | Toxic to pets |
| Mountain Pine | Direct sun (at least 4-6 hours) | When the soil surface starts to dry, then soak thoroughly | Mildly toxic to pets |
| Mountain Rimu | Bright indirect light (just back from a sunny window) | Every 7-14 days; keep soil consistently moist, especially in summer | Mildly toxic to pets |
| Mountain Sandwort | Direct sun (at least 4-6 hours) | Weekly during establishment; drought-tolerant once established | Pet-safe |
| Mouse-ear Hawkweed | Direct sun (at least 4-6 hours) | Infrequent — allow soil to dry between waterings | Mildly toxic to pets |
| Mr Bowling Ball Arborvitae | Direct sun (at least 4-6 hours) | Twice weekly while establishing; weekly thereafter | Mildly toxic to pets |
| Mrs D.F. Maxwell Cornish heath | Direct sun (at least 4-6 hours) | Weekly while establishing; every 2–3 weeks once established | Pet-safe |
| Mugo Pine | Direct sun (at least 4-6 hours) | Water weekly while establishing the first year, then only in prolonged drought | Mildly toxic to pets |
| Muhly Grass | Direct sun (at least 4-6 hours) | Water regularly the first season to establish, then only in drought, roughly every 2 weeks | Mildly toxic to pets |
| Muir's Sage | Direct sun (at least 4-6 hours) | Low; drought tolerant once established | Pet-safe |
| Mulberry Wine prickly heath | Bright indirect light (just back from a sunny window) | Regular; keep consistently moist | Toxic to pets |
| Mule-Ear Oncidium | Bright indirect light (just back from a sunny window) | When roots approach dry, about every 4-6 days year-round | Pet-safe |
| Munby's Rock Rose | Direct sun (at least 4-6 hours) | Very low — drought-tolerant once established | Mildly toxic to pets |
| Munstead Wood Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Muscari 'White Magic' | Direct sun (at least 4-6 hours) | Rainfall in most settings; water in dry spring spells | Pet-safe |
| Muscari armeniacum | Direct sun (at least 4-6 hours) | Rainfall in most settings; water in dry spring spells | Pet-safe |
| Musk Mallow | Direct sun (at least 4-6 hours) | Low to moderate once established | Pet-safe |
| Muster-John-Henry | Direct sun (at least 4-6 hours) | Once or twice weekly; allow the top 3 cm of soil to dry between waterings | Mildly toxic to pets |
| Myretoun Ruby winter heath | Direct sun (at least 4-6 hours) | Weekly for new plants in the first season; every 2–3 weeks for established plants during dry spells | Pet-safe |
| Myriophyllum spicatum | Direct sun (at least 4-6 hours) | Continuously submerged; maintain pond level so plants sit in 0.5-3 m of water | Mildly toxic to pets |
| Nahanni Fern | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the top 2 cm of soil begins to dry, roughly weekly in dry spells | Mildly toxic to pets |
| Naked Crocus | Bright indirect light (just back from a sunny window) | Low to moderate — prefers moisture during active growth; dry in summer | Mildly toxic to pets |
| Namaqualand Sage | Direct sun (at least 4-6 hours) | Low; sparingly once established | Pet-safe |
| Nana Lutea Hinoki Cypress | Direct sun (at least 4-6 hours) | Every 5-7 days while establishing, then when the top few cm of soil dry | Mildly toxic to pets |
| Nandina Firepower | Direct sun (at least 4-6 hours) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| Nandina Gulf Stream | Direct sun (at least 4-6 hours) | Weekly deep watering while establishing, then every 10-14 days in dry spells | Toxic to pets |
| Nandina Harbour Dwarf | Bright indirect light (just back from a sunny window) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| Nandina Obsessed | Direct sun (at least 4-6 hours) | Weekly while establishing, then every 10-14 days once mature | Toxic to pets |
| nannyberry | Bright indirect light (just back from a sunny window) | Weekly for first two seasons; infrequently once established | Mildly toxic to pets |
| Naomi Hakone Grass | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water 1-2 times weekly, more in heat | Mildly toxic to pets |
| Narcissus 'February Gold' | Direct sun (at least 4-6 hours) | Moist during autumn-to-spring growth; dry through summer dormancy | Toxic to pets |
| Narcissus 'Hawera' | Direct sun (at least 4-6 hours) | Keep soil evenly moist during active growth (autumn rooting through spring flowering); largely dry in summer dormancy | Toxic to pets |
| Narcissus 'Ice Follies' | Direct sun (at least 4-6 hours) | Moist in spring growth; drier through summer dormancy | Toxic to pets |
| Narcissus 'Jetfire' | Direct sun (at least 4-6 hours) | Moist during spring growth; drier through summer dormancy | Toxic to pets |
| Narcissus 'Minnow' | Direct sun (at least 4-6 hours) | Evenly moist while in leaf and flower; dry in summer dormancy | Toxic to pets |
| Narcissus 'Pipit' | Direct sun (at least 4-6 hours) | Moist in spring growth; drier through summer dormancy | Toxic to pets |
| Narcissus 'Tahiti' | Direct sun (at least 4-6 hours) | Moist in spring growth; drier through summer dormancy | Toxic to pets |
| Narcissus 'Tete-a-Tete' | Direct sun (at least 4-6 hours) | Moist in spring growth; drier through summer dormancy | Toxic to pets |
| Narcissus 'Thalia' | Direct sun (at least 4-6 hours) | Moist in spring growth; drier through summer dormancy | Toxic to pets |
| narrow small-reed | Direct sun (at least 4-6 hours) | Keep constantly moist to wet; suited to boggy, saturated, or seasonally flooded soils | Pet-safe |
| Narrow-Leaf Bird of Paradise | Direct sun (at least 4-6 hours) | Allow soil to dry well between waterings; approximately every 10–21 days in the growing season, very infrequent in winter | Toxic to pets |
| Narrow-Leaf Coneflower | Direct sun (at least 4-6 hours) | Water to establish in year one, then only in prolonged drought | Pet-safe |
| Narrow-leaf Zinnia | Direct sun (at least 4-6 hours) | When top 3-4 cm of soil is dry, roughly every 5-10 days | Pet-safe |
| Narrow-Leaved Ash | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Pet-safe |
| Narrow-leaved Biarum | Direct sun (at least 4-6 hours) | Light watering in autumn–spring active growth; completely dry in summer | Toxic to pets |
| Narrow-Leaved Evening Primrose | Direct sun (at least 4-6 hours) | Every 10–14 days; very drought-tolerant once established | Pet-safe |
| Narrow-leaved Everlasting Pea | Bright indirect light (just back from a sunny window) | Low to moderate — water during prolonged drought only once established | Mildly toxic to pets |
| Narrow-leaved Gentian | Bright indirect light (just back from a sunny window) | Moderate; allow the top centimetre of soil to dry between waterings | Pet-safe |
| Narrow-leaved Glade Fern | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water when the top 2 cm begin to dry, roughly every 5-7 days in dry weather | Mildly toxic to pets |
| Narrow-leaved Water Plantain | Direct sun (at least 4-6 hours) | Marginal aquatic; submerged 0–20 cm over the crown | Mildly toxic to pets |
| Narrow-leaved Watsonia | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry during active growth, roughly every 7-14 days | Mildly toxic to pets |
| Narrowleaf gazania | Direct sun (at least 4-6 hours) | Every 10–21 days once established; twice weekly when newly planted | Mildly toxic to pets |
| Narrowleaf Milkweed | Direct sun (at least 4-6 hours) | Low; drought-tolerant, minimal supplemental watering | Toxic to pets |
| Nasturtium | Direct sun (at least 4-6 hours) | Weekly watering | Pet-safe |
| Nathalie's Ramonda | Medium indirect light (a couple of metres from a window) | Once or twice a week in the growing season; minimal in winter | Pet-safe |
| Nearly Wild Rose | Direct sun (at least 4-6 hours) | Deeply once a week, more in heat | Pet-safe |
| Needle Grass | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Mildly toxic to pets |
| Neglected Pink | Direct sun (at least 4-6 hours) | Sparingly; allow soil to dry between waterings | Toxic to pets |
| Nelumbo 'Baby Doll' | Direct sun (at least 4-6 hours) | Always submerged; keep 8-25 cm of water over the crown | Mildly toxic to pets |
| Nelumbo 'Momo Botan' | Direct sun (at least 4-6 hours) | Always submerged; keep 10-30 cm of water over the crown | Mildly toxic to pets |
| Nelumbo 'Mrs. Perry D. Slocum' | Direct sun (at least 4-6 hours) | Always submerged; keep 15-45 cm of water over the crown | Mildly toxic to pets |
| Nelumbo lutea | Direct sun (at least 4-6 hours) | Always submerged; keep 15-60 cm of standing water over the crown | Mildly toxic to pets |
| Nelumbo nucifera | Direct sun (at least 4-6 hours) | Permanently submerged rhizome in still water with warm emergent growth | Mildly toxic to pets |
| Nematanthus 'Cheerio' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Pet-safe |
| Nematanthus 'Freckles' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Pet-safe |
| Nematanthus 'Tropicana' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Nematanthus wettsteinii | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Pet-safe |
| Nemesia 'Sunsatia Cranberry' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 2-3 days in warm weather | Pet-safe |
| Nemesia strumosa 'Poetry Blue' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 2-3 days in warm weather | Pet-safe |
| Neon Tangerine Calendula | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Nepeta 'Six Hills Giant' | Direct sun (at least 4-6 hours) | When soil is dry to a few centimetres; infrequently once established | Mildly toxic to pets |
| Nepeta 'Walker's Low' | Direct sun (at least 4-6 hours) | When the top few centimetres are dry; weekly while establishing | Mildly toxic to pets |
| Nepeta racemosa 'Blue Wonder' | Direct sun (at least 4-6 hours) | When the top few centimetres are dry; weekly while establishing | Mildly toxic to pets |
| Nepeta sibirica 'Souvenir d'André Chaudron' | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry; sparingly once established | Mildly toxic to pets |
| Nerved Catmint | Direct sun (at least 4-6 hours) | Every 7–10 days in the growing season; much less in winter | Pet-safe |
| net-vein camellia | Bright indirect light (just back from a sunny window) | Regularly; consistent moisture throughout the year | Mildly toxic to pets |
| Netted Chain Fern | Medium indirect light (a couple of metres from a window) | Keep continuously moist to wet; check every 3-5 days and never allow drying | Mildly toxic to pets |
| Netted Iris | Direct sun (at least 4-6 hours) | Low — dry in summer dormancy; moderate when in growth | Toxic to pets |
| Nettle-leaved Bellflower | Medium indirect light (a couple of metres from a window) | Moderate — keep consistently moist, especially in summer | Pet-safe |
| Nettle-leaved Mullein | Direct sun (at least 4-6 hours) | Every 10–14 days during dry spells; seldom needed once established | Mildly toxic to pets |
| Nevada Bitterroot | Direct sun (at least 4-6 hours) | Moderate in spring; completely dry in summer dormancy | Pet-safe |
| Nevada Lewisia | Bright indirect light (just back from a sunny window) | Moderate in spring; almost none in summer dormancy | Mildly toxic to pets |
| New Dawn Rose | Direct sun (at least 4-6 hours) | Deeply once a week in the growing season; more during establishment or drought | Pet-safe |
| New England Aster | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water weekly, more in heat | Pet-safe |
| New England Aster 'Purple Dome' | Direct sun (at least 4-6 hours) | Keep evenly moist; water deeply during dry spells, about weekly | Pet-safe |
| New England Aster 'Purple Dome' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7 days in summer | Mildly toxic to pets |
| New Guinea Impatiens | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, often every 1-3 days in warm weather | Pet-safe |
| New Mexico Giant Hyssop | Direct sun (at least 4-6 hours) | Every 7–14 days once established | Pet-safe |
| New York aster | Direct sun (at least 4-6 hours) | Weekly during the growing season; less frequent once established in cool climates | Pet-safe |
| New York Aster 'Fellowship' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| New York Fern | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water when the top 2-3 cm begin to dry, roughly weekly in dry spells | Mildly toxic to pets |
| New York Ironweed | Direct sun (at least 4-6 hours) | Keep consistently moist; water weekly when rainfall is short | Mildly toxic to pets |
| New Zealand Everlasting Daisy | Direct sun (at least 4-6 hours) | Occasional; tolerant of dry spells once established | Mildly toxic to pets |
| New Zealand Gentian | Bright indirect light (just back from a sunny window) | Keep moist but never waterlogged; reduce in winter | Mildly toxic to pets |
| New Zealand Snowberry | Medium indirect light (a couple of metres from a window) | Every 7 days during the growing season; reduce in winter | Mildly toxic to pets |
| New Zealand Tree Fuchsia | Bright indirect light (just back from a sunny window) | Regular — consistent moisture | Pet-safe |
| Nicholas Hakone Grass | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water 1-2 times weekly, more in heat | Mildly toxic to pets |
| Nicotiana × sanderae 'Starmaker Lime' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Toxic to pets |
| Nicotiana alata 'Perfume Deep Purple' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Toxic to pets |
| Nicotiana sylvestris | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 4-6 days | Toxic to pets |
| Night Sky Petunia | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of compost feels dry, typically every 2-4 days in warm weather; containers may need daily watering in midsummer heat | Pet-safe |
| Night-Blooming Cereus | Bright indirect light (just back from a sunny window) | When the top few cm of mix is dry, roughly every 1-2 weeks in growth | Pet-safe |
| Night-scented stock | Direct sun (at least 4-6 hours) | Every 7–10 days; allow soil to dry between waterings | Pet-safe |
| Nikko Blue Bigleaf Hydrangea | Bright indirect light (just back from a sunny window) | When the top 3–5 cm of soil is dry, roughly every 3–5 days in summer; reduce in winter | Toxic to pets |
| Nikko bog rosemary | Bright indirect light (just back from a sunny window) | Consistently moist; never dry out | Toxic to pets |
| Nikko Fir | Direct sun (at least 4-6 hours) | Weekly when establishing; reduced once established | Pet-safe |
| Nile Sage | Bright indirect light (just back from a sunny window) | Moderate; consistent moisture preferred | Pet-safe |
| Ninebark 'Diabolo' | Direct sun (at least 4-6 hours) | Weekly while establishing; established plants only in prolonged drought | Mildly toxic to pets |
| Ninja Foamflower | Medium indirect light (a couple of metres from a window) | Every 5–7 days; increase in warm or dry periods | Pet-safe |
| Ninja Tiarella | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water deeply once or twice a week during dry periods | Mildly toxic to pets |
| Nivalis flowering quince | Bright indirect light (just back from a sunny window) | Weekly during establishment; rainfall usually sufficient once established | Mildly toxic to pets |
| Nobile Dendrobium | Bright indirect light (just back from a sunny window) | Frequently in spring-summer growth, then sharply reduced over the cool winter rest | Pet-safe |
| Noble Cape Primrose | Bright indirect light (just back from a sunny window) | every 5–9 days in active growth, every 14 days in winter | Pet-safe |
| Noble Cymbidium | Bright indirect light (just back from a sunny window) | Keep lightly and evenly moist, about every 5-7 days, reduced in winter | Pet-safe |
| Noble Fir | Direct sun (at least 4-6 hours) | Regular watering during establishment; naturally sustained by Pacific Northwest rainfall | Pet-safe |
| Nodding Enkianthus | Bright indirect light (just back from a sunny window) | Regularly; maintain even soil moisture | Mildly toxic to pets |
| Nodding Sage | Direct sun (at least 4-6 hours) | Low to moderate; allow soil to dry between waterings | Pet-safe |
| Nodding Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist to seasonally wet; tolerates more moisture than most Trilliums. | Mildly toxic to pets |
| Nodding Wand Flower | Direct sun (at least 4-6 hours) | Heavy from early spring to late summer; reduced in autumn and winter | Mildly toxic to pets |
| Nootka Cypress | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Mildly toxic to pets |
| Nootka Cypress | Direct sun (at least 4-6 hours) | Regularly during establishment; tolerates wet or dry once mature | Pet-safe |
| Nootka Lupin | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 10-14 days once established | Toxic to pets |
| Nordmann Fir | Direct sun (at least 4-6 hours) | Weekly during establishment; relies on rainfall once established | Pet-safe |
| Northern Blazing Star | Direct sun (at least 4-6 hours) | Every 1-2 weeks once established; more often during establishment | Pet-safe |
| Northern Japanese Hemlock | Bright indirect light (just back from a sunny window) | Weekly during growing season; less in winter | Pet-safe |
| Northern Red Oak | Direct sun (at least 4-6 hours) | Regular deep watering in the first 2-3 years; established trees are moderately drought-tolerant | Mildly toxic to pets |
| Northern Sea Oats | Bright indirect light (just back from a sunny window) | Water to keep soil moist, deeply once or twice weekly in dry periods | Mildly toxic to pets |
| Northwind Switch Grass | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water deeply every 1-2 weeks while young | Mildly toxic to pets |
| Northwind Switchgrass | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks when mature | Pet-safe |
| Norway Maple | Direct sun (at least 4-6 hours) | Deeply every 7-14 days during the first three growing seasons; established mature trees are largely self-sufficient but benefit from watering during severe drought | Mildly toxic to pets |
| Norway Spruce | Direct sun (at least 4-6 hours) | When the top centimetre of soil begins to dry, often daily in summer | Mildly toxic to pets |
| Nottingham Catchfly | Bright indirect light (just back from a sunny window) | Low; allow soil to dry between waterings | Mildly toxic to pets |
| Nuccio's Gems camellia | Bright indirect light (just back from a sunny window) | Regular; consistent moisture essential from summer through bud set | Mildly toxic to pets |
| Nummularioides Wax Plant | Bright indirect light (just back from a sunny window) | Every 7-10 days in the growing season; roughly every 2 weeks in winter | Pet-safe |
| Nun's Orchid | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, roughly every 3-5 days | Mildly toxic to pets |
| Nuphar lutea | Direct sun (at least 4-6 hours) | Permanently submerged roots; keep crown in 0.3-2.5 m of water | Mildly toxic to pets |
| Nuphar polysepala | Direct sun (at least 4-6 hours) | Permanently submerged roots; keep crown in 0.3-2 m of water | Mildly toxic to pets |
| Nymphaea 'Albert Greenberg' | Direct sun (at least 4-6 hours) | Permanently submerged in warm still water | Mildly toxic to pets |
| Nymphaea 'Attraction' | Direct sun (at least 4-6 hours) | Permanently submerged; maintain pond level, top up in summer heat | Mildly toxic to pets |
| Nymphaea 'Chromatella' | Direct sun (at least 4-6 hours) | Permanently submerged; keep pond level steady | Mildly toxic to pets |
| Nymphaea 'Director George T. Moore' | Direct sun (at least 4-6 hours) | Permanently submerged in warm still water | Mildly toxic to pets |
| Nymphaea 'Escarboucle' | Direct sun (at least 4-6 hours) | Permanently submerged; keep pond level constant | Mildly toxic to pets |
| Nymphaea 'Firecrest' | Direct sun (at least 4-6 hours) | Permanently submerged in still water | Mildly toxic to pets |
| Nymphaea 'Gonnere' | Direct sun (at least 4-6 hours) | Permanently submerged in still or very slow-moving water | Mildly toxic to pets |
| Nymphaea 'James Brydon' | Direct sun (at least 4-6 hours) | Permanently submerged; maintain steady pond level | Mildly toxic to pets |
| Nymphaea 'Marliacea Albida' | Direct sun (at least 4-6 hours) | Permanently submerged; keep pond level steady | Mildly toxic to pets |
| Nymphaea 'Marliacea Carnea' | Direct sun (at least 4-6 hours) | Permanently submerged; keep pond level steady | Mildly toxic to pets |
| Nymphaea 'Perry's Fire Opal' | Direct sun (at least 4-6 hours) | Permanently submerged; keep pond level steady | Mildly toxic to pets |
| Nymphaea 'Pygmaea Helvola' | Direct sun (at least 4-6 hours) | Permanently submerged in shallow still water | Mildly toxic to pets |
| Nymphaea 'Pygmaea Rubra' | Direct sun (at least 4-6 hours) | Permanently submerged in shallow still water | Mildly toxic to pets |
| Nymphaea 'Sioux' | Direct sun (at least 4-6 hours) | Permanently submerged; keep pond level steady | Mildly toxic to pets |
| Nymphaea capensis | Direct sun (at least 4-6 hours) | Permanently submerged in warm still water | Mildly toxic to pets |
| Nymphoides peltata | Direct sun (at least 4-6 hours) | Permanently submerged; maintain stable pond level | Mildly toxic to pets |
| Nyssa sylvatica | Direct sun (at least 4-6 hours) | Weekly while establishing; keep soil moist to wet | Mildly toxic to pets |
| Oak Fern | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the top 2 cm begins to dry, roughly weekly in dry weather | Mildly toxic to pets |
| Oak-leaf Primulina | Medium indirect light (a couple of metres from a window) | Allow soil to become fairly dry between waterings | Mildly toxic to pets |
| Oakleaf Hydrangea | Bright indirect light (just back from a sunny window) | Keep soil moist while establishing; then water deeply during dry spells, roughly weekly in summer heat | Toxic to pets |
| Oakleaf Hydrangea 'Snow Queen' | Bright indirect light (just back from a sunny window) | Roughly weekly, about 2.5 cm (1 inch) per week while establishing; deep-soak when the top 5 cm of soil dries | Toxic to pets |
| Odontoglossum crispum | Bright indirect light (just back from a sunny window) | Keep evenly moist year-round, watering roughly every 3-5 days so the mix never fully dries | Pet-safe |
| Ohio Goldenrod | Direct sun (at least 4-6 hours) | Moderate to high — keep soil consistently moist | Pet-safe |
| Ohio Spiderwort | Bright indirect light (just back from a sunny window) | Weekly to fortnightly; drought-tolerant once established | Mildly toxic to pets |
| Oklahoma Salmon zinnia | Direct sun (at least 4-6 hours) | Every 3–5 days; adjust for rainfall and temperature | Pet-safe |
| Old Father Live Forever | Bright indirect light (just back from a sunny window) | Water when the top 3–5 cm of compost is dry, roughly every 10–14 days; reduce in winter | Toxic to pets |
| Old Gold Juniper | Direct sun (at least 4-6 hours) | Water regularly the first season; afterward only during sustained drought | Toxic to pets |
| Old Man's Beard | Direct sun (at least 4-6 hours) | During establishment water deeply every 5-7 days; once established, water only during prolonged dry spells | Toxic to pets |
| old-fashioned weigela | Direct sun (at least 4-6 hours) | Weekly during the first growing season; once or twice per month during dry spells when established | Pet-safe |
| Oleander | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days once established | Toxic to pets |
| Oliver's impatiens | Medium indirect light (a couple of metres from a window) | Every 4–7 days; moderate and consistent | Pet-safe |
| Olivia Rose Austin | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Olympiad Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly during growth | Pet-safe |
| Olympic Mullein | Direct sun (at least 4-6 hours) | Every 14–21 days; very drought-tolerant once established | Mildly toxic to pets |
| Olympic St. John's Wort | Direct sun (at least 4-6 hours) | Every 10–14 days; drought-tolerant once established | Toxic to pets |
| Oncidium ornithorhynchum | Bright indirect light (just back from a sunny window) | Every 4-6 days in growth, as the mix nears dryness | Pet-safe |
| Oncidium sphacelatum | Bright indirect light (just back from a sunny window) | Every 4-7 days in growth, when the mix approaches dryness | Pet-safe |
| One-flowered Clintonia | Low light (north window or shaded room) | Maintain consistently moist soil; water deeply when the top 2 cm begins to dry | Mildly toxic to pets |
| Only the Lonely Tobacco Plant | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Ophir Mugo Pine | Direct sun (at least 4-6 hours) | Water weekly during the first growing season, then only in extended drought | Mildly toxic to pets |
| Opium poppy | Direct sun (at least 4-6 hours) | Weekly during establishment; every 10–14 days once growing strongly | Toxic to pets |
| Orache-Leaved Sun Rose | Direct sun (at least 4-6 hours) | Very low — once every 3–4 weeks in summer; rely on rainfall in other seasons | Mildly toxic to pets |
| Orange coneflower | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| Orange Glow Firethorn | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Orange Lily | Direct sun (at least 4-6 hours) | When top 2–3 cm of soil is dry | Toxic to pets |
| Orange New Zealand sedge | Bright indirect light (just back from a sunny window) | Regular watering until established; moderate thereafter | Pet-safe |
| Orange Queen Epimedium | Medium indirect light (a couple of metres from a window) | Weekly during establishment and dry spells; established clumps are notably drought-tolerant | Mildly toxic to pets |
| Orange River Lily | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days during the growing season | Toxic to pets |
| orange sinningia | Bright indirect light (just back from a sunny window) | Every 5–7 days during active growth; stop completely during winter dormancy | Pet-safe |
| Orange Sneezeweed | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Orange Snow Ball Cactus | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is dry, roughly every 7-10 days in spring and summer; every 4-6 weeks in autumn; none or barely any in winter | Pet-safe |
| Orange Star | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days during active growth | Toxic to pets |
| Orange Stonecrop | Direct sun (at least 4-6 hours) | Every 10-14 days when establishing; virtually rain-fed once mature | Pet-safe |
| Orchid | Bright indirect light (just back from a sunny window) | Once a week — soak the medium thoroughly, then drain | Pet-safe |
| Orchid Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Pet-safe |
| Oreocharis auricula | Medium indirect light (a couple of metres from a window) | When the top 1-2 cm of soil is dry, roughly every 4-6 days in growth | Mildly toxic to pets |
| Oriental Arborvitae | Direct sun (at least 4-6 hours) | Weekly when establishing (first 1–2 seasons); every 2–3 weeks once established; reduce in winter | Mildly toxic to pets |
| Oriental Bittersweet | Direct sun (at least 4-6 hours) | Extremely drought-tolerant once established; supplemental watering is rarely needed except in the first season | Toxic to pets |
| oriental fountain grass | Direct sun (at least 4-6 hours) | Every 10–14 days once established; more frequent during establishment | Pet-safe |
| Oriental Hornbeam | Direct sun (at least 4-6 hours) | Low once established; water during first 2 seasons only | Pet-safe |
| Oriental Poppy 'Beauty of Livermere' | Direct sun (at least 4-6 hours) | Once a week during active growth; reduce as plants go summer-dormant | Toxic to pets |
| Oriental Poppy 'Patty's Plum' | Direct sun (at least 4-6 hours) | Once a week during spring growth; reduce markedly as summer dormancy approaches | Toxic to pets |
| Oriental Spruce | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; regular moisture during first 2–3 years | Mildly toxic to pets |
| Oriental Sweetgum | Direct sun (at least 4-6 hours) | Weekly during establishment; drought-tolerant once established | Mildly toxic to pets |
| Ornamental Plum 'Nigra' | Direct sun (at least 4-6 hours) | Weekly while establishing; little once mature | Toxic to pets |
| Orpheus Flower | Medium indirect light (a couple of metres from a window) | Lightly and consistently, keeping the root zone barely moist but never wet | Mildly toxic to pets |
| Orpine | Direct sun (at least 4-6 hours) | Every 1–2 weeks during dry spells; drought-tolerant once established | Mildly toxic to pets |
| Orssich's Holiday Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in the growing season; reduce to every 2-3 weeks during the autumn rest | Pet-safe |
| Osbeck's Rock Rose | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Mildly toxic to pets |
| Osmunda regalis 'Purpurascens' | Medium indirect light (a couple of metres from a window) | Keep soil constantly moist to wet; check every 2-3 days in growth | Mildly toxic to pets |
| Osmunda spectabilis | Medium indirect light (a couple of metres from a window) | Keep wet to consistently moist at all times; water whenever the surface is not damp | Pet-safe |
| Ossorio Gold Umbrella Pine | Bright indirect light (just back from a sunny window) | Once every 7-10 days, keeping soil consistently moist throughout the growing season | Mildly toxic to pets |
| Ostbo Red Mountain Laurel | Medium indirect light (a couple of metres from a window) | Regular; maintain even moisture | Toxic to pets |
| Osteospermum 'Akila Daisy White' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 4-7 days | Pet-safe |
| Osteospermum 'Sunny Serena White' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 4-7 days | Pet-safe |
| Osteospermum 'Voltage Yellow' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 4-7 days | Pet-safe |
| Othello Ligularia | Medium indirect light (a couple of metres from a window) | Keep permanently moist; water deeply 2-3 times weekly, daily during heat | Mildly toxic to pets |
| Ovate Maiden Fern | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water when the top 2-3 cm begin to dry, roughly weekly in dry weather | Mildly toxic to pets |
| Overdam Feather Reed Grass | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 2 weeks once established | Pet-safe |
| Overdam Variegated Feather Reed Grass | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry, about weekly; tolerates occasionally damp soil | Pet-safe |
| Oxalis tetraphylla | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-10 days in active growth | Toxic to pets |
| Oxeye daisy | Direct sun (at least 4-6 hours) | Minimal once established; water during prolonged drought only | Mildly toxic to pets |
| Oxford and Cambridge Grape Hyacinth | Bright indirect light (just back from a sunny window) | Rainfall usually sufficient; water during prolonged dry spells in spring | Toxic to pets |
| Oxlip | Medium indirect light (a couple of metres from a window) | Regularly; keep soil consistently moist, especially in summer | Mildly toxic to pets |
| Oxydendrum arboreum | Direct sun (at least 4-6 hours) | Weekly while establishing; regular watering in dry spells | Mildly toxic to pets |
| Pachystachys Lutea | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 4-7 days in growth | Mildly toxic to pets |
| Pacific Dogwood | Bright indirect light (just back from a sunny window) | Regular deep watering, especially in summer; do not let the root zone dry out | Pet-safe |
| Pacific Silver Fir | Bright indirect light (just back from a sunny window) | Regularly during establishment; relies on natural rainfall when mature | Pet-safe |
| Pacific Yew | Low light (north window or shaded room) | Weekly during establishment; every 2 weeks once established | Toxic to pets |
| Pacifica Vinca | Direct sun (at least 4-6 hours) | Every 3–5 days outdoors in summer heat; allow topsoil to partially dry between waterings | Toxic to pets |
| Paeonia lactiflora 'Bowl of Beauty' | Direct sun (at least 4-6 hours) | Deeply about once a week through spring and early summer; taper off after dormancy | Toxic to pets |
| Paeonia lactiflora 'Festiva Maxima' | Direct sun (at least 4-6 hours) | Deeply about once a week during the growing season; less once dormant | Toxic to pets |
| Paeonia lactiflora 'Karl Rosenfield' | Direct sun (at least 4-6 hours) | Deeply about once a week during active growth; reduce after dormancy | Toxic to pets |
| Paeonia mlokosewitschii | Direct sun (at least 4-6 hours) | Deeply about once a week in the growing season; minimal once dormant | Toxic to pets |
| Pagoda Dogwood | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water deeply weekly in the first two seasons and during droughts | Pet-safe |
| Pagoda Fawn Lily | Medium indirect light (a couple of metres from a window) | Regular during spring growing season; reduce significantly after dormancy | Mildly toxic to pets |
| Painted Daisy | Direct sun (at least 4-6 hours) | Weekly during active growth; reduce after flowering and in winter | Mildly toxic to pets |
| Painted Flowering Maple | Bright indirect light (just back from a sunny window) | Water when top 1–2 cm of compost dries; less in winter | Mildly toxic to pets |
| Painted Lady Gladiolus | Direct sun (at least 4-6 hours) | Moderate during autumn–spring growing season; completely dry in summer dormancy | Toxic to pets |
| Painted Lady sweet pea | Direct sun (at least 4-6 hours) | Every 3–5 days; daily in hot weather | Toxic to pets |
| Painted Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist throughout the growing season; never allow soil to dry out. | Mildly toxic to pets |
| Palace Purple coral bells | Medium indirect light (a couple of metres from a window) | Once or twice per week in growing season; reduce in winter | Pet-safe |
| Pale Beardtongue | Direct sun (at least 4-6 hours) | Low; highly drought-tolerant once established | Mildly toxic to pets |
| Pale Purple Coneflower | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry; weekly while establishing, then rarely | Pet-safe |
| Pale Purple Coneflower | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry; highly drought-tolerant once established after the first season | Mildly toxic to pets |
| Pale Vygie | Direct sun (at least 4-6 hours) | Every 3–4 weeks established; more frequent in first season | Pet-safe |
| Pale Yellow Fritillary | Bright indirect light (just back from a sunny window) | Regular during active growth; reduce once foliage dies back in early summer | Toxic to pets |
| Pale Yellow Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist through spring; reduce during summer dormancy | Mildly toxic to pets |
| Pale-Leaved Sunflower | Direct sun (at least 4-6 hours) | Weekly until established, then every 1-2 weeks | Pet-safe |
| Pale-Spike Lobelia | Bright indirect light (just back from a sunny window) | Moderate; keep moist but tolerates brief dry spells | Toxic to pets |
| Palibin Dwarf Korean Lilac | Direct sun (at least 4-6 hours) | Every 7-10 days during dry spells; drought-tolerant once established | Mildly toxic to pets |
| Palinha's Rock Rose | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Mildly toxic to pets |
| palm sedge | Medium indirect light (a couple of metres from a window) | Consistently moist; water whenever the top 2 cm of soil dries | Pet-safe |
| Palmer's Indian Mallow | Direct sun (at least 4-6 hours) | Low; deep, infrequent irrigation once established | Mildly toxic to pets |
| Palmetto Sedge | Medium indirect light (a couple of metres from a window) | When the top 2 cm of soil is dry, roughly every 5-8 days | Pet-safe |
| Palo Alto Sweetgum | Direct sun (at least 4-6 hours) | Regular in first 2–3 years; moderate once established | Mildly toxic to pets |
| Pampas Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; thereafter only in prolonged drought | Pet-safe |
| Panicle Hydrangea 'Pinky Winky' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 3-5 days in summer | Toxic to pets |
| Panicle Hydrangea 'Pinky Winky' | Direct sun (at least 4-6 hours) | When the top 2-4 cm of soil is dry, regularly through summer | Toxic to pets |
| Panicle Hydrangea 'Vanilla Strawberry' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 3-5 days in summer | Toxic to pets |
| Panicled Corn Lily | Direct sun (at least 4-6 hours) | Moderate in autumn-to-spring growth; completely dry in summer | Mildly toxic to pets |
| Pansy | Direct sun (at least 4-6 hours) | Twice-weekly watering | Pet-safe |
| Pansy Orchid | Bright indirect light (just back from a sunny window) | Every 3-5 days; up to 2-3 times weekly in warm, dry spells | Pet-safe |
| Pansy Orchid | Medium indirect light (a couple of metres from a window) | When the surface of the mix begins to dry, roughly every 4-6 days | Pet-safe |
| Paper Birch | Direct sun (at least 4-6 hours) | Weekly in the first 3 years; every 10–14 days once established, more in summer heat | Pet-safe |
| Paperwhite Narcissus | Bright indirect light (just back from a sunny window) | Keep roots consistently moist during forcing; reduce after flowering | Toxic to pets |
| Paphiopedilum 'Pinocchio' | Medium indirect light (a couple of metres from a window) | Every 4-7 days; keep evenly moist | Pet-safe |
| Paphiopedilum bellatulum | Medium indirect light (a couple of metres from a window) | Every 5-8 days; keep lightly moist, never waterlogged | Pet-safe |
| Paphiopedilum malipoense | Medium indirect light (a couple of metres from a window) | Every 4-7 days; keep evenly moist, never bone-dry | Pet-safe |
| Paphiopedilum venustum | Medium indirect light (a couple of metres from a window) | Every 4-7 days; keep evenly moist | Pet-safe |
| Paprika yarrow | Direct sun (at least 4-6 hours) | Water when top 5–8 cm of soil is dry; drought-tolerant once established | Mildly toxic to pets |
| Paraboea rufescens | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 6-9 days | Mildly toxic to pets |
| Parker's jasmine | Bright indirect light (just back from a sunny window) | Every 10–14 days; highly drought-tolerant once established | Mildly toxic to pets |
| Parrot Gladiolus | Direct sun (at least 4-6 hours) | Weekly during active growth; reduce once foliage yellows; cease during summer dormancy | Toxic to pets |
| Parrot Pitcher Plant | Direct sun (at least 4-6 hours) | Keep permanently wet, standing in 1-3 cm of water (tray method); it tolerates brief flooding well | Pet-safe |
| Parrotia persica | Direct sun (at least 4-6 hours) | Weekly while establishing in the first 2-3 years; rarely thereafter | Mildly toxic to pets |
| Parsons Juniper | Direct sun (at least 4-6 hours) | Water deeply during the first season; afterward only in extended drought | Toxic to pets |
| Parthenocissus henryana | Bright indirect light (just back from a sunny window) | Keep young plants moist; water established plants only in drought | Toxic to pets |
| Parthenocissus quinquefolia | Bright indirect light (just back from a sunny window) | Water through the first one to two seasons, then only in drought | Toxic to pets |
| Parthenocissus tricuspidata | Bright indirect light (just back from a sunny window) | Water young plants in dry spells until established, then rarely | Toxic to pets |
| Partridge Pea | Direct sun (at least 4-6 hours) | Low; water during establishment then rely on rainfall | Mildly toxic to pets |
| Partridgeberry | Low light (north window or shaded room) | Keep soil evenly moist; water when the top 1–2 cm begins to dry | Pet-safe |
| Passiflora 'Incense' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, every 3-5 days in summer heat | Mildly toxic to pets |
| Passiflora caerulea | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days in growth | Mildly toxic to pets |
| Passiflora incarnata | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 5-7 days in summer | Mildly toxic to pets |
| Pat Austin Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season, increasing in hot, dry spells | Pet-safe |
| Path Rush | Direct sun (at least 4-6 hours) | Minimal supplemental watering needed once established; tolerates periodic flooding and dry spells | Pet-safe |
| Pau's Germander | Direct sun (at least 4-6 hours) | Very infrequently; relies on natural rainfall once established | Mildly toxic to pets |
| Paul's Glory Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Paul's Himalayan Musk Rose | Direct sun (at least 4-6 hours) | Deep soak weekly through the first two growing seasons; established plants rarely need watering | Pet-safe |
| Paulownia tomentosa | Direct sun (at least 4-6 hours) | Water weekly while establishing in the first two seasons, then rely largely on rainfall | Mildly toxic to pets |
| Pazazz Mix Portulaca | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is completely dry, roughly every 7-14 days | Mildly toxic to pets |
| Peace lily | Medium indirect light (a couple of metres from a window) | As soon as the leaves start to droop slightly, usually every 5-7 days | Toxic to pets |
| Peace Rose | Direct sun (at least 4-6 hours) | Deeply 1-2 times per week, more in heat | Pet-safe |
| Peach-leaved Bellflower 'Chettle Charm' | Bright indirect light (just back from a sunny window) | Once a week in dry weather; reduce in autumn and winter | Mildly toxic to pets |
| Peacock Moraea | Direct sun (at least 4-6 hours) | Regular watering autumn to late spring; completely dry in summer | Toxic to pets |
| Peacock Pink | Direct sun (at least 4-6 hours) | Low; allow soil to dry thoroughly between waterings | Mildly toxic to pets |
| Pelargonium 'Ardens' | Direct sun (at least 4-6 hours) | When the soil is fully dry, about every 10-14 days in growth; minimal in summer rest | Toxic to pets |
| Pelargonium 'Bird Dancer' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 7-10 days in growth | Toxic to pets |
| Pelargonium 'Deacon Barbecue' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 4-8 days in growth | Toxic to pets |
| Pelargonium 'Deacon Fireball' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 4-8 days in growth | Toxic to pets |
| Pelargonium 'Deacon Mandarin' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 4-8 days in growth | Toxic to pets |
| Pelargonium 'Distinction' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Dolly Varden' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-7 days in growth | Toxic to pets |
| Pelargonium 'Flower of Spring' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost dries, roughly every 5-7 days in active growth | Toxic to pets |
| Pelargonium 'Frank Headley' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Happy Thought' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Lord Bute' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of compost is dry, roughly every 5-9 days in summer | Toxic to pets |
| Pelargonium 'Madame Layal' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm of compost dries, about every 5-9 days in summer | Toxic to pets |
| Pelargonium 'Mr Wren' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Mrs Pollock' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Mystery' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, about every 5-7 days in summer | Toxic to pets |
| Pelargonium 'Occold Lagoon' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 4-7 days in summer | Toxic to pets |
| Pelargonium 'Occold Shield' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Paton's Unique' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Toxic to pets |
| Pelargonium 'Paul Crampel' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Rollisson's Unique' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, about every 5-7 days in summer | Toxic to pets |
| Pelargonium 'Scarlet Unique' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-7 days in summer | Toxic to pets |
| Pelargonium 'Solferino' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Stellar Hannaford Star' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Tip Top Duet' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Vancouver Centennial' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 5-10 days in growth | Toxic to pets |
| Pelargonium 'Wilhelm Langguth' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, about every 5-7 days in summer | Toxic to pets |
| Pelargonium fulgidum | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in growth | Toxic to pets |
| Pelargonium peltatum 'Amethyst' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost dries, often every 3-7 days in summer baskets | Toxic to pets |
| Pelargonium peltatum 'Barrocas' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 4-7 days in summer | Toxic to pets |
| Pelargonium peltatum 'Roi des Balcons Lilas' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost dries, often every 3-7 days in summer | Toxic to pets |
| Pelargonium peltatum 'Sofie Cascade' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost dries, often every 3-7 days in summer | Toxic to pets |
| Pelargonium peltatum 'Tomcat' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days in summer | Toxic to pets |
| Pelargonium x domesticum 'Burgundy' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Pelargonium x domesticum 'Carisbrooke' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Pelargonium x domesticum 'Chocolate Blotch' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 5-7 days in growth | Toxic to pets |
| Pelargonium x domesticum 'Hazel Carey' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 5-7 days in growth | Toxic to pets |
| Pelargonium x domesticum 'Lavender Grand Slam' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Pelargonium-Flowered Stork's Bill | Direct sun (at least 4-6 hours) | Water sparingly; allow soil to dry out between waterings | Mildly toxic to pets |
| Pelotazo Mallow | Direct sun (at least 4-6 hours) | Every 10–21 days in summer; monthly or less in winter | Pet-safe |
| Pencil Pine | Bright indirect light (just back from a sunny window) | Keep permanently moist; never let it dry out, watering deeply during any dry period | Mildly toxic to pets |
| Pencilled Cranesbill | Medium indirect light (a couple of metres from a window) | Occasional watering during establishment; largely self-sufficient once established | Pet-safe |
| Penelope Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly through the growing season, more in heat | Pet-safe |
| Penisetum massaicum Red Bunny Tails | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about weekly; more often in pots and heat | Pet-safe |
| Pennsylvania Sedge | Medium indirect light (a couple of metres from a window) | Water to establish, then largely self-sufficient; occasional deep watering in extended drought | Mildly toxic to pets |
| Penny Yellow Viola | Bright indirect light (just back from a sunny window) | When the top 1–2 cm of soil is dry, roughly every 4–6 days | Mildly toxic to pets |
| Penstemon 'Garnet' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries, roughly weekly in summer | Mildly toxic to pets |
| Penstemon 'Husker Red' | Direct sun (at least 4-6 hours) | Water to establish, then only during prolonged drought; drought-tolerant once settled | Mildly toxic to pets |
| Penstemon 'Raven' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries, roughly weekly in summer | Mildly toxic to pets |
| Penstemon 'Sour Grapes' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries, about weekly in summer | Mildly toxic to pets |
| Penstemon 'Stapleford Gem' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; roughly weekly in summer, less in cool spells | Mildly toxic to pets |
| Penstemon barbatus 'Rondo' | Direct sun (at least 4-6 hours) | Water to establish, then sparingly; drought-tolerant once established | Mildly toxic to pets |
| Penstemon heterophyllus 'Electric Blue' | Direct sun (at least 4-6 hours) | Water to establish, then minimally; highly drought-tolerant once settled | Mildly toxic to pets |
| Penther's Cape Primrose | Bright indirect light (just back from a sunny window) | every 7–10 days during active growth, every 14–21 days in winter | Pet-safe |
| Peony | Direct sun (at least 4-6 hours) | Deep watering once a week in dry spells | Toxic to pets |
| Peony 'Sarah Bernhardt' | Direct sun (at least 4-6 hours) | Deeply once a week during active growth and budding, more in drought; reduce after flowering and through dormancy | Toxic to pets |
| Peony Lotus | Direct sun (at least 4-6 hours) | Aquatic — permanently in still or gently circulating water | Mildly toxic to pets |
| Peregrina | Direct sun (at least 4-6 hours) | Every 7–14 days in the growing season; every 2–3 weeks in winter | Toxic to pets |
| Perennial Candytuft | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| Perez's Sea Lavender | Direct sun (at least 4-6 hours) | Every 2–3 weeks when established; less in winter | Pet-safe |
| Perfoliate Bellwort | Medium indirect light (a couple of metres from a window) | Moderate in spring; established plants are drought-tolerant once dormant. | Pet-safe |
| Persian Barrenwort | Medium indirect light (a couple of metres from a window) | Weekly for the first 1–2 seasons; established plants need watering only during extreme drought | Mildly toxic to pets |
| Persian Carpet zinnia | Direct sun (at least 4-6 hours) | Every 5–7 days; highly drought tolerant once established | Pet-safe |
| Persian Catmint | Direct sun (at least 4-6 hours) | Every 7–14 days; less in cooler seasons | Pet-safe |
| Persian Jewels love-in-a-mist | Direct sun (at least 4-6 hours) | Weekly | Mildly toxic to pets |
| Persian Lily | Direct sun (at least 4-6 hours) | Once per week during active spring growth; completely dry in summer dormancy | Toxic to pets |
| Persian Shield | Bright indirect light (just back from a sunny window) | When the top 2-3 cm (1 inch) of soil dries | Mildly toxic to pets |
| Persian Violet | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is just dry, roughly every 3-5 days | Pet-safe |
| Persicaria amplexicaulis 'Alba' | Direct sun (at least 4-6 hours) | Keep soil moist; water every 3-5 days in dry spells, especially in sun | Mildly toxic to pets |
| Persicaria amplexicaulis 'Blackfield' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days during dry weather | Mildly toxic to pets |
| Persicaria amplexicaulis 'Firetail' | Direct sun (at least 4-6 hours) | Keep evenly moist; water whenever the surface starts to dry, more in heat | Mildly toxic to pets |
| Persicaria bistorta 'Superba' | Direct sun (at least 4-6 hours) | Keep soil moist; water every 3-5 days in dry conditions | Mildly toxic to pets |
| Persicaria orientalis | Direct sun (at least 4-6 hours) | About twice a week in summer, keeping soil evenly moist | Mildly toxic to pets |
| Peruvian zinnia | Direct sun (at least 4-6 hours) | Once or twice weekly; allow the top 3 cm of soil to dry between waterings | Pet-safe |
| Petrocosmea iodioides | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of mix feels barely dry, roughly every 5-7 days | Mildly toxic to pets |
| Petrocosmea kerrii | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, roughly every 5-8 days | Mildly toxic to pets |
| Petrocosmea nervosa | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of mix is just dry, about every 5-7 days | Mildly toxic to pets |
| Petrocosmea parryorum | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, roughly every 5-8 days | Mildly toxic to pets |
| Petunia | Direct sun (at least 4-6 hours) | Even moisture — every 1-2 days for hanging baskets in heat | Pet-safe |
| Petunia 'Supertunia Royal Velvet' | Direct sun (at least 4-6 hours) | When the top 2-3cm of soil is dry, frequently daily for containers in summer | Pet-safe |
| Petunia 'Supertunia Vista Bubblegum' | Direct sun (at least 4-6 hours) | When the top 2-3cm of soil is dry, often daily for containers in summer heat | Pet-safe |
| Petunia 'Tidal Wave Silver' | Direct sun (at least 4-6 hours) | When the top 2-3cm of soil is dry; containers may need daily watering in summer | Pet-safe |
| Petunia 'Wave Purple' | Direct sun (at least 4-6 hours) | When the top 2-3cm of soil is dry, often daily in summer for baskets and containers | Pet-safe |
| Petunia axillaris | Direct sun (at least 4-6 hours) | When the top 2-3cm of soil is dry; avoid both drought and waterlogging | Pet-safe |
| Peve Minaret Bald Cypress | Direct sun (at least 4-6 hours) | Keep soil consistently moist to wet; water every 5-7 days in dry periods | Mildly toxic to pets |
| Phalaenopsis 'Brother Sara Gold' | Bright indirect light (just back from a sunny window) | When the bark is nearly dry, typically every 7-10 days | Pet-safe |
| Phalaenopsis 'Liodoro' | Bright indirect light (just back from a sunny window) | About every 7-10 days, when the bark begins to dry and roots silver over | Pet-safe |
| Phalaenopsis-type Dendrobium | Bright indirect light (just back from a sunny window) | Regularly through warm active growth; reduced over a short, cooler, drier winter | Pet-safe |
| Pheasant Tail Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; drought-tolerant thereafter | Mildly toxic to pets |
| Pheasant's Tail Grass | Bright indirect light (just back from a sunny window) | Every 7–14 days in the growing season; minimal in winter | Pet-safe |
| Phegopteris connectilis | Low light (north window or shaded room) | Keep soil evenly moist; water when the top 1-2 cm begins to dry, roughly every 4-6 days in growth | Pet-safe |
| Phegopteris hexagonoptera | Low light (north window or shaded room) | Keep consistently moist; water when the surface starts to dry, about every 4-6 days during growth | Pet-safe |
| Philadelphus 'Snowbelle' | Direct sun (at least 4-6 hours) | Weekly while establishing, then in dry spells | Mildly toxic to pets |
| Philadelphus 'Virginal' | Direct sun (at least 4-6 hours) | Weekly while establishing, then occasional deep watering | Mildly toxic to pets |
| Philadelphus microphyllus | Direct sun (at least 4-6 hours) | Occasional deep soak once established | Mildly toxic to pets |
| Philippe Vapelle Cranesbill | Bright indirect light (just back from a sunny window) | Moderate; water during extended dry spells | Mildly toxic to pets |
| Phlomis-Like Sage | Direct sun (at least 4-6 hours) | Every 2-3 weeks once established | Pet-safe |
| Phlox drummondii 'Intensia Cabernet' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days | Pet-safe |
| Phlox maculata 'Alpha' | Direct sun (at least 4-6 hours) | Keep evenly moist; water deeply 1-2 times weekly in dry spells, more in heat | Pet-safe |
| Phlox of Sheep Annual Phlox | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Phlox paniculata 'Starfire' | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply about weekly, more in heat and drought | Pet-safe |
| Phlox subulata 'Emerald Blue' | Direct sun (at least 4-6 hours) | Water when soil is dry; drought-tolerant once established | Pet-safe |
| Phoenicean Juniper | Direct sun (at least 4-6 hours) | Water weekly when young; essentially rainfall-dependent once established | Mildly toxic to pets |
| Phragmipedium 'Living Fire' | Bright indirect light (just back from a sunny window) | Keep constantly moist to wet; water every 1-3 days, often standing the pot in a shallow tray of clean water | Pet-safe |
| Phragmipedium besseae | Bright indirect light (just back from a sunny window) | Keep constantly moist to wet; water every 1-3 days and many growers stand the pot in 1-2 cm of clean water | Pet-safe |
| Phragmipedium longifolium | Bright indirect light (just back from a sunny window) | Keep constantly moist; water every 1-3 days, often with the pot standing in a shallow tray of clean water | Pet-safe |
| Phragmites australis | Direct sun (at least 4-6 hours) | Keep wet to shallowly flooded year-round | Mildly toxic to pets |
| Physocarpus opulifolius 'Center Glow' | Direct sun (at least 4-6 hours) | Water weekly during the first year; established plants are drought-tolerant and need water only in extended dry spells | Mildly toxic to pets |
| Physocarpus opulifolius 'Coppertina' | Direct sun (at least 4-6 hours) | Weekly while establishing; every 1-2 weeks in dry spells once mature | Mildly toxic to pets |
| Physocarpus opulifolius 'Diabolo' | Direct sun (at least 4-6 hours) | Weekly while establishing; every 1-2 weeks in dry spells once mature | Mildly toxic to pets |
| Physocarpus opulifolius 'Little Devil' | Direct sun (at least 4-6 hours) | Weekly while establishing; every 1-2 weeks in dry spells once mature | Mildly toxic to pets |
| Physocarpus opulifolius 'Summer Wine' | Direct sun (at least 4-6 hours) | Weekly while establishing; every 1-2 weeks in dry spells once mature | Mildly toxic to pets |
| Pieris japonica Cavatine | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water when the top 3-4 cm is dry, about weekly while establishing | Toxic to pets |
| Pieris japonica Valley Rose | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water when the top 3-4 cm is dry, roughly weekly while establishing | Toxic to pets |
| Pigeon Orchid | Bright indirect light (just back from a sunny window) | Frequently in warm growth, allowing brief drying between waterings | Pet-safe |
| Pilalo Fuchsia | Bright indirect light (just back from a sunny window) | Freely in growth; reduce in winter | Pet-safe |
| Pillans' Watsonia | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-14 days during spring and early summer | Mildly toxic to pets |
| Pin Oak | Direct sun (at least 4-6 hours) | Regular watering during establishment; tolerates periodic waterlogging and moist soils once established | Mildly toxic to pets |
| Pincushion flower | Direct sun (at least 4-6 hours) | Once or twice weekly | Pet-safe |
| Pincushion Flower | Direct sun (at least 4-6 hours) | Water regularly while establishing, then when the top few centimetres of soil are dry | Mildly toxic to pets |
| Pineapple Lily | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days during the growing season | Toxic to pets |
| Pineapple Upsidedown Cake Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil is dry, about every 5-7 days during active growth | Toxic to pets |
| Pineleaf Penstemon | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; rarely in winter | Pet-safe |
| Pinemat manzanita | Direct sun (at least 4-6 hours) | Low to moderate; allow soil to dry between waterings once established | Pet-safe |
| Ping Pong Purple globe amaranth | Direct sun (at least 4-6 hours) | Every 5–7 days; allow soil surface to dry slightly | Pet-safe |
| Pinguicula 'Tina' | Bright indirect light (just back from a sunny window) | Keep lightly moist in summer; let the surface dry slightly between waterings in winter | Mildly toxic to pets |
| Pinguicula lusitanica | Bright indirect light (just back from a sunny window) | Keep permanently wet; stand in shallow water at all times | Mildly toxic to pets |
| Pinguicula primuliflora | Bright indirect light (just back from a sunny window) | Keep permanently wet; stand in shallow water year-round, around 1-2 cm | Mildly toxic to pets |
| Pink Anthurium | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days in growth | Toxic to pets |
| Pink Arisaema | Low light (north window or shaded room) | Keep moist through the growing season once growth appears, watering when the surface dries; reduce sharply as the leaf dies back to dormancy. | Toxic to pets |
| Pink Calla Lily | Bright indirect light (just back from a sunny window) | Frequently during active growth — keep soil consistently moist; reduce sharply after flowering | Toxic to pets |
| Pink Cascade Tamarisk | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Pet-safe |
| Pink Coreopsis | Direct sun (at least 4-6 hours) | Moderate to high; keep soil evenly moist | Pet-safe |
| Pink Deutzia | Direct sun (at least 4-6 hours) | Every 7-10 days during dry periods; drought-tolerant once established | Pet-safe |
| Pink Evening Primrose | Direct sun (at least 4-6 hours) | Every 1–2 weeks once established; less in cool periods | Mildly toxic to pets |
| Pink Fawn Lily | Medium indirect light (a couple of metres from a window) | Regular watering in spring; minimal to none during summer dormancy | Mildly toxic to pets |
| Pink Flowering Dogwood | Bright indirect light (just back from a sunny window) | Weekly deep watering; increase in summer heat | Pet-safe |
| Pink Ice Plant | Direct sun (at least 4-6 hours) | Weekly in spring and summer growing season; every 2–3 weeks in autumn; rarely in winter | Mildly toxic to pets |
| Pink Knock Out Rose | Direct sun (at least 4-6 hours) | About 2.5 cm of water weekly, deep soak | Pet-safe |
| Pink Lady flowering quince | Bright indirect light (just back from a sunny window) | Weekly when establishing; fortnightly in dry weather once established | Mildly toxic to pets |
| Pink Moth Orchid | Bright indirect light (just back from a sunny window) | When the bark approaches dryness, typically every 7-10 days | Pet-safe |
| Pink Mountain Heath | Bright indirect light (just back from a sunny window) | Regular — maintain consistent moisture | Mildly toxic to pets |
| Pink mountain heather | Direct sun (at least 4-6 hours) | Consistently moist throughout the growing season; less in winter | Mildly toxic to pets |
| Pink Muhly Grass | Direct sun (at least 4-6 hours) | Every 10-14 days during the first growing season; minimal supplemental irrigation once established | Pet-safe |
| Pink Pampas Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; afterwards only in prolonged drought | Pet-safe |
| Pink Pampas Grass | Direct sun (at least 4-6 hours) | Weekly during the establishment year; established plants are largely self-sufficient on rainfall in temperate climates | Mildly toxic to pets |
| Pink Penny Cranesbill | Bright indirect light (just back from a sunny window) | Water once or twice a week during dry periods; reduce in winter | Pet-safe |
| Pink Pewter Dead Nettle | Medium indirect light (a couple of metres from a window) | Every 7–10 days; increase in dry or sunny spells | Pet-safe |
| Pink Pitcher Plant | Direct sun (at least 4-6 hours) | Keep constantly moist to wet — sit in 2–5 cm of standing water during the growing season | Mildly toxic to pets |
| Pink Pussytoes | Direct sun (at least 4-6 hours) | Low; water only when soil is completely dry | Pet-safe |
| Pink Quill | Bright indirect light (just back from a sunny window) | Mist 2-3 times per week; soak the medium sparingly | Mildly toxic to pets |
| Pink Rain Lily | Direct sun (at least 4-6 hours) | Regular in summer; minimal in winter | Mildly toxic to pets |
| Pink Rock Jasmine | Direct sun (at least 4-6 hours) | Very sparingly; driest in winter | Pet-safe |
| Pink Senecio | Direct sun (at least 4-6 hours) | regular during the growing season, reduced in winter | Toxic to pets |
| Pink Skyrocket Foamflower | Medium indirect light (a couple of metres from a window) | Once or twice per week during the growing season; reduce in autumn and winter. | Mildly toxic to pets |
| Pink Spur Flower | Medium indirect light (a couple of metres from a window) | Moderate — water when top 3 cm of soil dries out | Mildly toxic to pets |
| Pink Storm Lily | Direct sun (at least 4-6 hours) | Moderate in summer growth; minimal in winter | Toxic to pets |
| Pink Surprise calendula | Direct sun (at least 4-6 hours) | Every 5–7 days; reduce in cool, wet periods | Pet-safe |
| Pink Tritonia | Direct sun (at least 4-6 hours) | Moderate during growth; dry to minimal in winter dormancy | Mildly toxic to pets |
| Pink Variable Heron's Bill | Direct sun (at least 4-6 hours) | Low — infrequent, allowing soil to dry between waterings | Mildly toxic to pets |
| Pink Vygie | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season; monthly or less in winter | Mildly toxic to pets |
| Piper's Bellflower | Direct sun (at least 4-6 hours) | Sparingly; allow near-drying between waterings | Pet-safe |
| Pipsissewa | Low light (north window or shaded room) | Sparingly — allow soil to dry almost completely between waterings; low water requirement | Mildly toxic to pets |
| Pires's Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in active growth; very sparingly during dormancy | Mildly toxic to pets |
| Pirri-Pirri Bur | Direct sun (at least 4-6 hours) | Fortnightly once established; drought-tolerant | Pet-safe |
| Pitcher Sage | Medium indirect light (a couple of metres from a window) | Every 2–4 weeks once established; deep water at planting | Mildly toxic to pets |
| PJM rhododendron | Bright indirect light (just back from a sunny window) | Weekly during establishment and dry spells; every 2 weeks once established | Toxic to pets |
| Plains Coreopsis | Direct sun (at least 4-6 hours) | Low; once established, water only during prolonged drought | Pet-safe |
| Plantain Thrift | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established | Mildly toxic to pets |
| Plantain-leaved Pussytoes | Bright indirect light (just back from a sunny window) | Low; drought-tolerant once established | Pet-safe |
| Playboy Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly | Pet-safe |
| Pleated Snowdrop | Medium indirect light (a couple of metres from a window) | Weekly during active growth (late winter–spring); minimal in summer dormancy | Toxic to pets |
| Plectranthus scutellarioides 'Black Dragon' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, often every 2-4 days in summer | Toxic to pets |
| Plectranthus scutellarioides 'Freckles' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Toxic to pets |
| Plectranthus scutellarioides 'Kong Rose' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Toxic to pets |
| Plectranthus scutellarioides 'Rainbow Festive Dance' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Toxic to pets |
| Plectranthus scutellarioides 'Wizard Scarlet' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Toxic to pets |
| Ploughman's Spikenard | Direct sun (at least 4-6 hours) | Low — water every 2–3 weeks in dry spells once established | Mildly toxic to pets |
| Plum Pudding Heuchera | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, about weekly | Pet-safe |
| Plumed cockscomb | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in summer | Pet-safe |
| Podophylla Rodgersia | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply 1-2 times weekly, more in heat | Mildly toxic to pets |
| Poet's Narcissus | Bright indirect light (just back from a sunny window) | Moderate to regular during growth; tolerates more moisture than most narcissi; drier in summer | Toxic to pets |
| Poet's Narcissus | Direct sun (at least 4-6 hours) | Once or twice weekly during active growth; allow to dry after foliage dies back | Toxic to pets |
| Poinsettia | Bright indirect light (just back from a sunny window) | When the top of the soil feels dry | Toxic to pets |
| Point Reyes bearberry | Direct sun (at least 4-6 hours) | Low once established; water weekly for the first 1–2 seasons | Pet-safe |
| Poke Milkweed | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water during dry spells, especially in sunnier sites | Toxic to pets |
| Poker alumroot | Bright indirect light (just back from a sunny window) | Every 7–14 days once established; more frequent when young | Pet-safe |
| Polypodium cambricum | Bright indirect light (just back from a sunny window) | Water during its winter growing season when the top few cm dry; keep drier in summer dormancy | Mildly toxic to pets |
| Polypodium cambricum 'Cambricum' | Bright indirect light (just back from a sunny window) | Water through its autumn-to-spring growing season when the top few cm dry; keep drier in summer | Mildly toxic to pets |
| Polystichum aculeatum | Low light (north window or shaded room) | Keep soil consistently moist; water every 5-7 days in dry spells once established | Pet-safe |
| Polystichum makinoi | Low light (north window or shaded room) | Keep evenly moist; water every 5-7 days during dry weather | Pet-safe |
| Polystichum neolobatum | Low light (north window or shaded room) | Keep consistently moist; water every 5-7 days in dry conditions | Pet-safe |
| Polystichum setiferum 'Divisilobum' | Low light (north window or shaded room) | Keep evenly moist; water deeply during dry spells, roughly weekly in summer | Pet-safe |
| Polystichum setiferum 'Plumosum Densum' | Low light (north window or shaded room) | Keep evenly moist; water deeply during dry spells, roughly weekly in summer | Pet-safe |
| Pomegranate Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, every 2-5 days in summer heat | Mildly toxic to pets |
| Pompon Dahlia 'Jowey Mirella' | Direct sun (at least 4-6 hours) | Deeply 2-3 times a week in summer once established; keep evenly moist while flowering | Toxic to pets |
| Pond Cypress | Direct sun (at least 4-6 hours) | Keep consistently moist; tolerates standing water and periodic flooding | Mildly toxic to pets |
| Pontederia cordata | Direct sun (at least 4-6 hours) | Keep in standing water year-round | Mildly toxic to pets |
| Pontederia cordata 'Alba' | Direct sun (at least 4-6 hours) | Keep in standing water year-round | Mildly toxic to pets |
| Pontederia cordata 'Pink Pons' | Direct sun (at least 4-6 hours) | Keep in standing water year-round | Mildly toxic to pets |
| Pony Tails Grass | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing, then minimal | Mildly toxic to pets |
| Poplar-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Low — establishment watering then rain-fed | Mildly toxic to pets |
| Poppy Anemone | Direct sun (at least 4-6 hours) | Moderate in spring, dry in summer | Toxic to pets |
| Porcupine Grass | Direct sun (at least 4-6 hours) | Weekly during the first growing season; once established, every 2–3 weeks or during prolonged drought. | Mildly toxic to pets |
| Portuguese heath | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2 weeks in the first summer; drought-tolerant once established | Pet-safe |
| Portuguese Squill | Direct sun (at least 4-6 hours) | Water moderately in spring; keep dry in summer | Toxic to pets |
| Portulaca grandiflora 'Sundial Mango' | Direct sun (at least 4-6 hours) | When the soil is dry several centimetres down, roughly every 7-10 days; less in cool spells | Toxic to pets |
| Portulaca oleracea 'Fairytales Cinderella' | Direct sun (at least 4-6 hours) | When the soil has dried several centimetres down, about every 7-10 days; more often only in extreme heat | Toxic to pets |
| Potomac Early snapdragon | Direct sun (at least 4-6 hours) | 2-3 times per week | Mildly toxic to pets |
| Pouch Flower | Medium indirect light (a couple of metres from a window) | When the top of the compost begins to feel barely dry | Mildly toxic to pets |
| PowWow Wild Berry coneflower | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2 weeks once established in dry spells | Pet-safe |
| Prairie Azure Sage | Direct sun (at least 4-6 hours) | Fortnightly once established | Pet-safe |
| Prairie Beardtongue | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Mildly toxic to pets |
| Prairie Blazing Star | Direct sun (at least 4-6 hours) | Moderate; weekly during establishment; drought-tolerant once established | Pet-safe |
| Prairie Bluebells | Bright indirect light (just back from a sunny window) | Water sparingly once established; once per week during the flowering period, far less once the plant enters summer dormancy. | Mildly toxic to pets |
| Prairie Coreopsis | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Pet-safe |
| Prairie Dock | Direct sun (at least 4-6 hours) | Every 2-4 weeks once established | Pet-safe |
| Prairie Dropseed | Direct sun (at least 4-6 hours) | Water regularly the first year to establish, then only in extended drought, roughly every 2-3 weeks | Mildly toxic to pets |
| Prairie Fire Switch Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; thereafter only in extended drought | Mildly toxic to pets |
| Prairie Gentian | Direct sun (at least 4-6 hours) | Low — drought tolerant once established | Pet-safe |
| Prairie Goldenrod | Direct sun (at least 4-6 hours) | Low — water only to establish; drought-tolerant once rooted | Pet-safe |
| Prairie Heart-Leaved Aster | Direct sun (at least 4-6 hours) | Low to moderate — drought tolerant | Pet-safe |
| Prairie June Grass | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; withhold water during summer dormancy | Pet-safe |
| Prairie Milkweed | Direct sun (at least 4-6 hours) | Moderate; tolerates moist conditions better than most milkweeds | Toxic to pets |
| Prairie Penstemon | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; weekly during establishment | Pet-safe |
| Prairie Rosinweed | Direct sun (at least 4-6 hours) | Water to establish, then only in extended drought; drought-tolerant once rooted | Mildly toxic to pets |
| Prairie Sky switch grass | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water deeply every 1-2 weeks while young | Mildly toxic to pets |
| Prairie Sky Switchgrass | Direct sun (at least 4-6 hours) | Weekly during first season; every 2–3 weeks once established | Pet-safe |
| Prairie Smoke | Direct sun (at least 4-6 hours) | Water to establish, then only in prolonged drought; drought-tolerant once rooted | Mildly toxic to pets |
| Prairie Trillium | Medium indirect light (a couple of metres from a window) | Water regularly to keep soil evenly moist during spring growing season; reduce significantly once dormant in midsummer | Mildly toxic to pets |
| Prairie Violet | Bright indirect light (just back from a sunny window) | Fortnightly or less once established; drought-tolerant | Pet-safe |
| Pretty Crocus | Direct sun (at least 4-6 hours) | Low — rainfall-dependent during active growth; fully dry during summer dormancy | Mildly toxic to pets |
| Pretty Face | Direct sun (at least 4-6 hours) | Sparingly; allow soil to dry completely between waterings, roughly every 14-21 days during active growth | Pet-safe |
| Prickly Crossandra | Bright indirect light (just back from a sunny window) | Every 5–7 days in growing season; reduce to every 10–14 days in winter | Pet-safe |
| Prickly heath | Bright indirect light (just back from a sunny window) | Regular; keep evenly moist | Toxic to pets |
| Prickly Heath Bell's Seedling | Bright indirect light (just back from a sunny window) | Regularly during the growing season; keep soil moist | Mildly toxic to pets |
| Prickly Juniper | Direct sun (at least 4-6 hours) | Water fortnightly when young; minimal irrigation once established | Mildly toxic to pets |
| Prickly Thrift | Direct sun (at least 4-6 hours) | Every 2–3 weeks; minimal watering in winter | Mildly toxic to pets |
| Pride of Rochester Deutzia | Direct sun (at least 4-6 hours) | Every 7-10 days during dry spells; drought-tolerant once established | Pet-safe |
| Prima Donna Magic Flower | Bright indirect light (just back from a sunny window) | Every 3–5 days during active growth; withhold entirely during dormancy | Pet-safe |
| Primrose | Medium indirect light (a couple of metres from a window) | Weekly watering | Toxic to pets |
| Primrose-leaf Streptocarpus | Medium indirect light (a couple of metres from a window) | every 5–8 days in the growing season, every 10–14 days in winter | Pet-safe |
| Primula × polyantha | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil starts to dry, roughly every 3-5 days | Toxic to pets |
| Primula farinosa | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth; water whenever the surface dries | Toxic to pets |
| Primula japonica | Bright indirect light (just back from a sunny window) | Keep wet at all times; never let the soil dry out | Toxic to pets |
| Primula malacoides | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil starts to dry, roughly every 3-5 days | Toxic to pets |
| Primula Obconica | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, roughly every 3-5 days while flowering | Mildly toxic to pets |
| Primulina 'Dreamtime' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, about every 7-10 days | Mildly toxic to pets |
| Primulina 'Loki' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Mildly toxic to pets |
| Primulina 'Patina' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 7-12 days | Mildly toxic to pets |
| Primulina heterotricha | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, about every 7-10 days | Mildly toxic to pets |
| Primulina linearifolia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Mildly toxic to pets |
| Primulina tamiana | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, about every 5-8 days | Mildly toxic to pets |
| Prince Albert's Yew | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply during dry spells and avoid letting the rootball dry out | Mildly toxic to pets |
| Prince of Wales Juniper | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing, then minimal | Mildly toxic to pets |
| Prince's feather | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7 days in summer | Mildly toxic to pets |
| Princess Alexandra of Kent Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in growth; more in heat or containers | Pet-safe |
| Princess Flower | Direct sun (at least 4-6 hours) | Roughly weekly; keep the soil evenly moist | Mildly toxic to pets |
| Profusion orange zinnia | Direct sun (at least 4-6 hours) | Every 5–7 days once established; more frequently in pots or extreme heat | Pet-safe |
| Profusion White Zinnia | Direct sun (at least 4-6 hours) | When the top 3–5 cm of soil is dry, roughly every 5–7 days in summer | Pet-safe |
| Prosperity Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season, more in heat | Pet-safe |
| Prostrate Blue Noble Fir | Direct sun (at least 4-6 hours) | Weekly when young, drought-tolerant once established | Mildly toxic to pets |
| Prostrate Speedwell | Direct sun (at least 4-6 hours) | Every 10–14 days; drought-tolerant once established | Pet-safe |
| Prunus 'Accolade' | Direct sun (at least 4-6 hours) | Water deeply weekly for the first two seasons; established trees rely on rainfall | Toxic to pets |
| Prunus 'Kanzan' | Direct sun (at least 4-6 hours) | Water deeply weekly for the first two seasons; established trees rely on rainfall | Toxic to pets |
| Prunus 'Spire' | Direct sun (at least 4-6 hours) | Water regularly for the first 2-3 years; established trees need water only in prolonged dry spells | Toxic to pets |
| Prunus maackii | Direct sun (at least 4-6 hours) | Water young trees deeply every 7-14 days in dry weather for the first two seasons; established trees are fairly drought-tolerant | Toxic to pets |
| Prunus padus | Direct sun (at least 4-6 hours) | Water regularly while establishing; mature trees rarely need irrigation except in extended drought | Toxic to pets |
| Prunus serrula | Direct sun (at least 4-6 hours) | Keep soil evenly moist in the first 2-3 years; established trees need watering only in prolonged summer drought | Toxic to pets |
| Prunus subhirtella 'Autumnalis' | Direct sun (at least 4-6 hours) | Water regularly during establishment; mature trees need watering only in prolonged summer drought | Toxic to pets |
| Przewalski's Leopard Plant | Medium indirect light (a couple of metres from a window) | Every 3-5 days in the growing season; soil should remain evenly moist to slightly wet | Mildly toxic to pets |
| Przewalskii Ligularia | Medium indirect light (a couple of metres from a window) | Keep constantly moist; water deeply 2-3 times weekly, more in heat | Mildly toxic to pets |
| Pseudolarix amabilis | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing; mature trees mostly rainfall-dependent but watered in drought | Mildly toxic to pets |
| Pumila Dwarf Pampas Grass | Direct sun (at least 4-6 hours) | Weekly during establishment; afterwards only in drought | Pet-safe |
| Pumila Norway Spruce | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing; deep soak when the top 5 cm of soil dries | Pet-safe |
| Pumila Pampas Grass | Direct sun (at least 4-6 hours) | Deeply once per week during the first growing season; established plants can survive on rainfall in most temperate climates | Mildly toxic to pets |
| Purity cosmos | Direct sun (at least 4-6 hours) | Every 5–7 days; highly drought tolerant once established | Pet-safe |
| Purple Bergenia | Medium indirect light (a couple of metres from a window) | Every 7-14 days; relatively drought-tolerant once established | Mildly toxic to pets |
| Purple Bugle | Medium indirect light (a couple of metres from a window) | Moderate; consistent moisture preferred | Mildly toxic to pets |
| Purple Coneflower | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; about weekly while establishing, then only in drought | Pet-safe |
| Purple Cyclamen | Medium indirect light (a couple of metres from a window) | Low in summer, moderate during active growth (late summer to spring) | Toxic to pets |
| Purple Dragon Dead Nettle | Medium indirect light (a couple of metres from a window) | Every 7–10 days; water more frequently in hot, dry periods | Pet-safe |
| Purple Fountain Grass | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil dries, roughly weekly in the ground and more often in containers | Pet-safe |
| Purple Giant Hyssop | Bright indirect light (just back from a sunny window) | Every 5–7 days; tolerates periodic wet spells | Pet-safe |
| Purple Heartleaf Bergenia | Medium indirect light (a couple of metres from a window) | Every 7–10 days during active growth; minimal in winter | Pet-safe |
| Purple Japanese Barberry | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Purple Jerusalem Sage | Direct sun (at least 4-6 hours) | Low — once every 2–3 weeks in the growing season; minimal in winter | Mildly toxic to pets |
| Purple Love Grass | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; more frequent during the first growing season | Pet-safe |
| Purple Milkweed | Direct sun (at least 4-6 hours) | Keep evenly moist; water during dry periods, especially while establishing | Toxic to pets |
| Purple Moor Grass | Bright indirect light (just back from a sunny window) | Regular; do not allow to dry out completely | Pet-safe |
| Purple Mountain Heath | Bright indirect light (just back from a sunny window) | Regular — keep consistently moist but never waterlogged | Mildly toxic to pets |
| Purple mountain heather | Direct sun (at least 4-6 hours) | Regularly; maintain consistent moisture throughout the growing season | Mildly toxic to pets |
| Purple Mountain Saxifrage | Bright indirect light (just back from a sunny window) | Every 5–7 days during the growing season; maintain slight moisture at all times | Pet-safe |
| Purple Mullein | Direct sun (at least 4-6 hours) | Every 7–10 days during active growth and dry spells | Mildly toxic to pets |
| Purple Needlegrass | Direct sun (at least 4-6 hours) | Very low; summer-dry, winter-wet cycle | Pet-safe |
| Purple Paintbrush | Direct sun (at least 4-6 hours) | Rarely; dry to very dry conditions | Mildly toxic to pets |
| Purple Poppy Mallow | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; deeply drought-tolerant | Pet-safe |
| Purple Prairie Clover | Direct sun (at least 4-6 hours) | Water to establish; thereafter drought-tolerant, rarely needs watering | Mildly toxic to pets |
| Purple Saxifrage | Bright indirect light (just back from a sunny window) | Water sparingly; allow soil to nearly dry between waterings in summer. | Pet-safe |
| Purple Siberian Melic | Bright indirect light (just back from a sunny window) | Every 1–2 weeks during the growing season | Pet-safe |
| Purple Sun African Daisy | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Purple toadflax | Direct sun (at least 4-6 hours) | Rarely needed once established; water young plants weekly until established | Mildly toxic to pets |
| Purple Vygie | Direct sun (at least 4-6 hours) | Every 3–4 weeks established; more in active growth | Pet-safe |
| Purple-flowered Sage | Bright indirect light (just back from a sunny window) | Moderate; water when the top 3–5 cm of soil is dry | Mildly toxic to pets |
| Purple-Top Germander | Bright indirect light (just back from a sunny window) | Weekly to fortnightly in summer; reduce in autumn and winter | Mildly toxic to pets |
| Purpurascens Flame Grass | Direct sun (at least 4-6 hours) | Weekly to establish, then mostly rainfall except in drought | Mildly toxic to pets |
| Pygmy Cactus | Bright indirect light (just back from a sunny window) | When soil is dry, about every 7-10 days in growth; keep dry in winter | Pet-safe |
| Pygmy Torch Amaranth | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Pygmy Water Lily | Direct sun (at least 4-6 hours) | Permanently aquatic — crown submerged 10–25 cm (4–10 in) below water surface | Pet-safe |
| Pyracantha angustifolia | Direct sun (at least 4-6 hours) | When the top 2-3 cm is dry, often daily in summer and every few days in cooler weather | Mildly toxic to pets |
| Pyramidal Bugle | Bright indirect light (just back from a sunny window) | Every 10–14 days; minimal irrigation once established | Mildly toxic to pets |
| Pyramidalis Arborvitae | Direct sun (at least 4-6 hours) | Two to three times weekly when establishing; weekly once rooted in | Mildly toxic to pets |
| Pyrenean Heron's Bill | Direct sun (at least 4-6 hours) | Water every 7-10 days in summer; minimal watering from autumn to spring | Mildly toxic to pets |
| Pyrenean Lily | Bright indirect light (just back from a sunny window) | Weekly during active growth; reduce after flowering | Toxic to pets |
| Pyrenean Merendera | Direct sun (at least 4-6 hours) | Minimal; naturally dry in summer | Toxic to pets |
| Pyrenean Ramonda | Medium indirect light (a couple of metres from a window) | Once or twice a week in the growing season; minimal in winter | Pet-safe |
| Pyrenean Rock Jasmine | Direct sun (at least 4-6 hours) | Low — water from below and keep dry in winter | Mildly toxic to pets |
| Pyrenean Saxifrage | Bright indirect light (just back from a sunny window) | Water sparingly; keep roots just moist in summer and very dry in winter. | Pet-safe |
| Pyrenean Star of Bethlehem | Bright indirect light (just back from a sunny window) | Low to moderate during growth; dry in summer dormancy | Toxic to pets |
| QIS Mix statice | Direct sun (at least 4-6 hours) | Every 7–10 days when actively growing; reduce in cool or wet weather | Pet-safe |
| Quaking Grass | Direct sun (at least 4-6 hours) | Water moderately; drought-tolerant once established | Mildly toxic to pets |
| Queen Elizabeth Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly, when the top few centimetres of soil are dry | Pet-safe |
| Queen Lime Red zinnia | Direct sun (at least 4-6 hours) | Regular; deep watering 2–3 times per week at soil level only | Pet-safe |
| Queen Mix Spider Flower | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Queen of Night Tulip | Direct sun (at least 4-6 hours) | Water at planting; rely on rainfall during growth; dry during dormancy | Toxic to pets |
| Queen of Sweden Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly through the growing season, more in heat | Pet-safe |
| Queen of the Night | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in summer; every 3-4 weeks in winter | Pet-safe |
| Queen of the Prairie | Bright indirect light (just back from a sunny window) | Frequently — keep soil consistently moist | Mildly toxic to pets |
| Queen Olga's Snowdrop | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry during active growth, roughly every 7-10 days | Toxic to pets |
| Queensland Kauri | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days | Mildly toxic to pets |
| Queeny Lime Orange zinnia | Direct sun (at least 4-6 hours) | Every 3–5 days in warm weather; reduce in cool spells | Pet-safe |
| Quercus coccinea | Direct sun (at least 4-6 hours) | Water young trees deeply every 10-14 days in dry weather through the first two seasons; established trees are drought-tolerant | Toxic to pets |
| Quercus robur 'Fastigiata' | Direct sun (at least 4-6 hours) | Water young trees deeply every 10-14 days in dry spells for the first two seasons; established oaks are very drought-tolerant | Toxic to pets |
| Ragged Robin | Bright indirect light (just back from a sunny window) | High; keep consistently moist | Mildly toxic to pets |
| Rainbow Leucothoe | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season; do not allow to dry out | Toxic to pets |
| Rainer's Bellflower | Direct sun (at least 4-6 hours) | Moderately during growth; sparingly in winter | Pet-safe |
| Rambling Sundew | Bright indirect light (just back from a sunny window) | Tray method during winter growing season (June–November); completely dry summer dormancy (December–May in the southern hemisphere) | Mildly toxic to pets |
| Ranunculus aquatilis | Direct sun (at least 4-6 hours) | Submerged with floating leaves; grow in 0.1-1 m of clear water | Toxic to pets |
| Ranunculus asiaticus | Direct sun (at least 4-6 hours) | Keep soil evenly moist during growth and bloom; reduce sharply as foliage yellows and the plant enters dormancy | Toxic to pets |
| Ranunculus asiaticus 'Cloni Success Arancio' | Direct sun (at least 4-6 hours) | Keep soil consistently moist but never waterlogged during active growth; reduce sharply as foliage yellows after flowering | Toxic to pets |
| Ranunculus asiaticus 'Elegance Bianco' | Direct sun (at least 4-6 hours) | Keep soil evenly moist during growth and flowering; cut back watering as foliage yellows at the end of the season | Toxic to pets |
| Ranunculus asiaticus 'Mache' | Direct sun (at least 4-6 hours) | Maintain even soil moisture during growth and flowering; taper off as the foliage yellows toward dormancy | Toxic to pets |
| Raspberry Splash Pulmonaria | Low light (north window or shaded room) | Keep soil evenly moist; water every 4-6 days in dry conditions, more in pots | Mildly toxic to pets |
| Rat Tail Cactus | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in spring and summer; reduce to every 3-4 weeks in winter | Pet-safe |
| Rattlesnake Master | Direct sun (at least 4-6 hours) | Water to establish, then rarely; highly drought-tolerant once rooted | Mildly toxic to pets |
| Rauwolff's Eminium | Direct sun (at least 4-6 hours) | Moderate during spring growing season; bone dry in summer dormancy | Toxic to pets |
| Ravenna Grass | Direct sun (at least 4-6 hours) | Weekly while establishing in year one, then only during prolonged drought | Mildly toxic to pets |
| Rayed Broom | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Toxic to pets |
| Recurved Leucothoe | Medium indirect light (a couple of metres from a window) | Regularly; maintain consistently moist soil throughout the growing season | Toxic to pets |
| Red amaranth | Direct sun (at least 4-6 hours) | Every 7–10 days once established | Mildly toxic to pets |
| Red Angel's Trumpet | Direct sun (at least 4-6 hours) | Every 3–5 days (keep evenly moist; allow top 2 cm to dry) | Toxic to pets |
| Red Baneberry | Medium indirect light (a couple of metres from a window) | 2–3 times per week in growing season; weekly when dormant | Toxic to pets |
| Red Barrenwort | Medium indirect light (a couple of metres from a window) | Weekly during establishment; established plants need watering only during extended summer drought | Mildly toxic to pets |
| Red Campion | Medium indirect light (a couple of metres from a window) | Moderate; keep moist | Mildly toxic to pets |
| Red escallonia | Direct sun (at least 4-6 hours) | Weekly during establishment; drought-tolerant once established | Mildly toxic to pets |
| Red Feather Clover | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Pet-safe |
| Red Fescue | Bright indirect light (just back from a sunny window) | Infrequent — drought-tolerant once established | Pet-safe |
| Red Fir | Direct sun (at least 4-6 hours) | Regular moisture; does not tolerate summer drought well | Pet-safe |
| red head fountain grass | Direct sun (at least 4-6 hours) | Every 7–10 days during the growing season; reduce in autumn; minimal in winter | Pet-safe |
| Red Horned Poppy | Direct sun (at least 4-6 hours) | Rarely; only during prolonged drought | Toxic to pets |
| Red Hot Poker | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days during the growing season | Mildly toxic to pets |
| Red larkspur | Direct sun (at least 4-6 hours) | Moderate — water once or twice weekly during spring growth; allow to dry out in summer dormancy | Toxic to pets |
| Red morning glory | Direct sun (at least 4-6 hours) | Once or twice a week; drought-tolerant when established | Toxic to pets |
| Red Orchid Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days in growth | Pet-safe |
| Red Osier Dogwood | Bright indirect light (just back from a sunny window) | Regularly; keep soil consistently moist | Pet-safe |
| Red Passion Flower | Direct sun (at least 4-6 hours) | Water thoroughly when the top 3-4 cm of soil dries out, roughly every 5-8 days; reduce in winter | Toxic to pets |
| Red Pine | Direct sun (at least 4-6 hours) | When the top few centimetres of soil dry; allow slight drying between waterings | Mildly toxic to pets |
| Red Prince Weigela | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Red Ray Switchgrass | Direct sun (at least 4-6 hours) | Every 1-2 weeks when established | Pet-safe |
| Red Rooster Sedge | Direct sun (at least 4-6 hours) | Keep evenly moist; water once or twice weekly in heat, less in cool weather | Mildly toxic to pets |
| Red Sentinel Astilbe | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water every 3-5 days in summer, more in heat or containers | Pet-safe |
| Red Sheep Laurel | Bright indirect light (just back from a sunny window) | Moderate; keep moist | Toxic to pets |
| Red Spider Lily | Direct sun (at least 4-6 hours) | Water sparingly; let the bulb go bone-dry during summer dormancy | Toxic to pets |
| Red Spruce | Direct sun (at least 4-6 hours) | Weekly in dry periods; naturally receives adequate moisture in humid northeastern climates | Pet-safe |
| Red Star Cluster | Direct sun (at least 4-6 hours) | Every 5–7 days; allow top 2–3 cm of soil to dry | Pet-safe |
| Red Torch Cleistocactus | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 10-14 days in summer and once every 4-6 weeks in winter | Pet-safe |
| Red Trillium | Medium indirect light (a couple of metres from a window) | Weekly during spring; reduce as plant goes dormant in midsummer | Mildly toxic to pets |
| Red Twig Dogwood 'Arctic Fire' | Direct sun (at least 4-6 hours) | Keep consistently moist; tolerates wet soil | Pet-safe |
| Red Valerian | Direct sun (at least 4-6 hours) | Drought-tolerant; water only to establish and in extended dry spells | Mildly toxic to pets |
| Red Vygie | Direct sun (at least 4-6 hours) | Every 3–4 weeks established; more frequent in first season | Pet-safe |
| Red-Topped Sage | Direct sun (at least 4-6 hours) | Water when the top 3 cm of soil feels dry | Pet-safe |
| red-twig dogwood | Bright indirect light (just back from a sunny window) | Weekly when young; tolerates both wet and dry once established | Mildly toxic to pets |
| Redvein Abutilon | Bright indirect light (just back from a sunny window) | Regularly in growth; reduced in winter | Mildly toxic to pets |
| Redvein enkianthus | Bright indirect light (just back from a sunny window) | Weekly during the growing season; reduce to every 2–3 weeks in winter | Mildly toxic to pets |
| Redvein Enkianthus Red Bells | Bright indirect light (just back from a sunny window) | Regularly during the growing season; reduce in winter | Mildly toxic to pets |
| Reed Sweet-grass | Direct sun (at least 4-6 hours) | Permanently wet; grows in standing water 15–45 cm deep | Pet-safe |
| Reed Sweetgrass | Direct sun (at least 4-6 hours) | Shallow to moderate aquatic; submerged 0–30 cm; tolerates winter flooding | Mildly toxic to pets |
| Reed-stem orchid | Bright indirect light (just back from a sunny window) | Every 4-5 days in warm growth; about weekly when cool | Pet-safe |
| Regel's Sage | Direct sun (at least 4-6 hours) | Moderate; approximately 2.5 cm (1 inch) per week | Pet-safe |
| Reitz's sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in active growth; cease in dormancy | Pet-safe |
| Renny Miniature Rose | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Pet-safe |
| Repandens Yew | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, roughly weekly while establishing | Toxic to pets |
| Revolution Hosta | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; deep watering 1-2 times weekly | Toxic to pets |
| Rheingold Arborvitae | Direct sun (at least 4-6 hours) | Twice weekly while establishing; weekly thereafter | Mildly toxic to pets |
| Rhipsalidopsis gaertneri | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Rhododendron 'Blue Peter' | Bright indirect light (just back from a sunny window) | Deeply once or twice a week in dry weather; keep consistently moist | Toxic to pets |
| Rhododendron 'Catawbiense Boursault' | Bright indirect light (just back from a sunny window) | Keep the rootball consistently moist; water deeply 1-2 times weekly in dry spells | Toxic to pets |
| Rhododendron 'Cunningham's White' | Bright indirect light (just back from a sunny window) | Keep consistently moist; water deeply 1-2 times weekly during dry spells | Toxic to pets |
| Rhododendron 'English Roseum' | Bright indirect light (just back from a sunny window) | Deeply once a week during the growing season; reduce in winter | Toxic to pets |
| Rhododendron 'Fastuosum Flore Pleno' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil begins to dry, roughly every 7-14 days depending on conditions | Toxic to pets |
| Rhododendron 'Nova Zembla' | Bright indirect light (just back from a sunny window) | Deeply once a week; more frequently during establishment and summer heat | Toxic to pets |
| Rhododendron 'Pink Pearl' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil begins to dry, roughly every 7-10 days during the growing season | Toxic to pets |
| Rhododendron 'PJM' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water deeply 1-2 times weekly in dry spells, more in heat | Toxic to pets |
| Rhododendron 'Roseum Elegans' | Bright indirect light (just back from a sunny window) | Deeply once a week during dry spells; keep consistently moist especially in summer | Toxic to pets |
| Rhyncholaeliocattleya 'Pastoral Innocence' | Bright indirect light (just back from a sunny window) | When the mix nears dry, roughly every 5-7 days in growth; reduced after flowering | Pet-safe |
| Ribbon Grass | Bright indirect light (just back from a sunny window) | Adaptable; keep moist for best foliage but tolerates dry once established | Mildly toxic to pets |
| rice cutgrass | Bright indirect light (just back from a sunny window) | Constantly moist to permanently flooded; thrives in standing water at or just above soil level | Pet-safe |
| Ridleyandra sp. | Medium indirect light (a couple of metres from a window) | When the top 1-2 cm of mix is just drying, roughly every 4-7 days | Mildly toxic to pets |
| Rieger begonia | Bright indirect light (just back from a sunny window) | When the top third of the mix is dry, roughly every 5-10 days | Toxic to pets |
| Rigid Draba | Direct sun (at least 4-6 hours) | Every 10–14 days during growth; almost none in winter | Pet-safe |
| Rigid Goldenrod | Direct sun (at least 4-6 hours) | Low — drought tolerant once established | Pet-safe |
| Rimu | Bright indirect light (just back from a sunny window) | When the top 5 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Ringed Sage | Direct sun (at least 4-6 hours) | Low to moderate; allow soil to dry between waterings | Pet-safe |
| Rise 'n' Shine Miniature Rose | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, around every 2-4 days in summer | Pet-safe |
| River Water Crowfoot | Direct sun (at least 4-6 hours) | Permanently submerged in flowing or moderately moving water 15–60 cm deep | Toxic to pets |
| Robert Chapman heather | Direct sun (at least 4-6 hours) | Regular watering for the first season; drought-tolerant once established | Pet-safe |
| Robin Hill serviceberry | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| Robinia pseudoacacia 'Frisia' | Direct sun (at least 4-6 hours) | Water weekly while establishing, then rely on rainfall | Toxic to pets |
| Roborowsky's Sage | Direct sun (at least 4-6 hours) | Moderate; keep soil evenly moist | Pet-safe |
| Rock Candytuft | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season; minimal in winter | Pet-safe |
| Rock Cress | Direct sun (at least 4-6 hours) | Low; water only when soil has dried out, roughly every 10–14 days in summer | Pet-safe |
| Rock Daffodil | Direct sun (at least 4-6 hours) | Minimal; moderate during active growth, completely dry in summer | Toxic to pets |
| Rock Jasmine | Direct sun (at least 4-6 hours) | Water moderately in spring and summer; reduce in autumn and winter | Pet-safe |
| Rock Speedwell | Bright indirect light (just back from a sunny window) | Once every 7–10 days during the growing season; reduce markedly in winter. | Pet-safe |
| Rocket candytuft | Direct sun (at least 4-6 hours) | Every 7–14 days; keep moist during establishment, reduce once rooted | Pet-safe |
| Rocket Mix Snapdragon | Direct sun (at least 4-6 hours) | When the top 2–3 cm of soil is dry, roughly every 5–7 days | Pet-safe |
| Rocket Mixed snapdragon | Direct sun (at least 4-6 hours) | Every 5–7 days; maintain consistent soil moisture | Pet-safe |
| Rocky Mountain Bee Plant | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Rocky Mountain Bristlecone Pine | Direct sun (at least 4-6 hours) | Deep watering every 2-3 weeks once established; let dry between | Mildly toxic to pets |
| Rocky Mountain Douglas Fir | Direct sun (at least 4-6 hours) | Moderate during establishment; drought-tolerant once established | Pet-safe |
| Rocky Mountain Juniper | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-6 days | Mildly toxic to pets |
| Rocky Mountain penstemon | Direct sun (at least 4-6 hours) | Every 14–21 days once established; very drought-tolerant | Mildly toxic to pets |
| Rocky Mountain Penstemon | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry, roughly every 10-21 days during the growing season | Mildly toxic to pets |
| Rodgersia Pinnata | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply 1-2 times weekly, more in heat | Mildly toxic to pets |
| Rodriguezia secunda | Bright indirect light (just back from a sunny window) | Every 2-4 days when mounted; every 4-6 days in a small basket, keeping it lightly moist | Mildly toxic to pets |
| Rolling Houseleek | Direct sun (at least 4-6 hours) | Low — extremely drought-tolerant | Mildly toxic to pets |
| Rooper's Red Hot Poker | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days during the growing season | Mildly toxic to pets |
| Rose | Direct sun (at least 4-6 hours) | Deep watering once a week, more in heat | Pet-safe |
| Rose campion | Direct sun (at least 4-6 hours) | Every 10–14 days; very drought-tolerant once established | Pet-safe |
| Rose grape | Bright indirect light (just back from a sunny window) | When the top 2-3cm of soil dries in growth; sparingly in winter | Mildly toxic to pets |
| Rose Grass | Direct sun (at least 4-6 hours) | Moderate during growth; almost dry in winter dormancy | Pet-safe |
| Rose of Sharon | Direct sun (at least 4-6 hours) | Weekly during dry spells; drought-tolerant once established | Mildly toxic to pets |
| Rose of Sharon 'Blue Bird' | Direct sun (at least 4-6 hours) | Weekly while establishing, then during dry or hot spells | Pet-safe |
| Rose of Sharon 'Diana' | Direct sun (at least 4-6 hours) | Weekly to establish, then during dry and hot periods | Pet-safe |
| Rose Pincushion Cactus | Direct sun (at least 4-6 hours) | When the soil is fully dry, roughly every 2 weeks in spring and summer; little to none in winter | Pet-safe |
| Rose Pincushion Cactus | Direct sun (at least 4-6 hours) | When soil is completely dry, roughly every 10-14 days in the growing season; once every 4-6 weeks in winter | Pet-safe |
| Rose Queen Barrenwort | Medium indirect light (a couple of metres from a window) | Water weekly until established; thereafter drought-tolerant, needing only occasional watering during prolonged dry spells | Mildly toxic to pets |
| Rose Queen Epimedium | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly weekly | Mildly toxic to pets |
| Rose Rain Lily | Direct sun (at least 4-6 hours) | Allow partial soil drying between waterings; dry-wet trigger cycle stimulates blooming | Toxic to pets |
| Rosebay Rhododendron | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in summer | Toxic to pets |
| Rosebay Willowherb | Direct sun (at least 4-6 hours) | Minimal once established; tolerates both dry and wet soils | Pet-safe |
| Rosemary Barberry | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry; established plants are drought-tolerant and may need watering only in prolonged dry spells | Mildly toxic to pets |
| Rosemary-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Low — water only during establishment | Mildly toxic to pets |
| Roseraie de l'Hay Rose | Direct sun (at least 4-6 hours) | Weekly during establishment; drought-tolerant once settled | Pet-safe |
| Rosette Rock Jasmine | Direct sun (at least 4-6 hours) | Weekly in the growing season; reduce significantly in winter | Mildly toxic to pets |
| Rosinweed | Direct sun (at least 4-6 hours) | Every 2-3 weeks once established | Pet-safe |
| Rossica Major rowan | Direct sun (at least 4-6 hours) | Regular during establishment; self-sufficient once mature | Mildly toxic to pets |
| Rosy Gladiolus | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days during active growth | Mildly toxic to pets |
| Rosy-Leaf Sage | Bright indirect light (just back from a sunny window) | Twice weekly in summer; weekly or less in cooler months | Mildly toxic to pets |
| Rothschild's Bulbophyllum | Medium indirect light (a couple of metres from a window) | Keep evenly moist in growth; water every 3-5 days | Pet-safe |
| Rothschild's Slipper Orchid | Bright indirect light (just back from a sunny window) | When the surface of the mix is approaching dry, roughly every 4-6 days | Mildly toxic to pets |
| Rotstrahlbusch Switch Grass | Direct sun (at least 4-6 hours) | Water weekly the first season; once established, only during prolonged drought | Mildly toxic to pets |
| Rough Blazing Star | Direct sun (at least 4-6 hours) | Water to establish, then only during extended drought | Pet-safe |
| Rough Chervil | Medium indirect light (a couple of metres from a window) | Moderate — rainfall-dependent | Toxic to pets |
| Rough Coneflower | Direct sun (at least 4-6 hours) | Every 2-3 weeks once established | Pet-safe |
| Rough Hawk's-beard | Direct sun (at least 4-6 hours) | Low — drought-tolerant, especially in the rosette year | Pet-safe |
| Rough Hawkbit | Direct sun (at least 4-6 hours) | Low — requires water only during prolonged summer drought | Pet-safe |
| Rough Sage | Direct sun (at least 4-6 hours) | Every 10–14 days once established | Mildly toxic to pets |
| Rough-leaved Cape Mallow | Direct sun (at least 4-6 hours) | Water when the top 3–4 cm of soil is dry | Mildly toxic to pets |
| Round-leaved Sage | Bright indirect light (just back from a sunny window) | Every 5–7 days during active growth | Pet-safe |
| Round-leaved Wintergreen | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water whenever the top 1–2 cm of soil begins to dry | Mildly toxic to pets |
| Round-lobed Hepatica | Medium indirect light (a couple of metres from a window) | Every 5–7 days during active growth; minimal in summer dormancy | Mildly toxic to pets |
| Rounded Sweetgum | Direct sun (at least 4-6 hours) | Weekly during establishment; less once mature | Mildly toxic to pets |
| Roundhead Prairie Clover | Direct sun (at least 4-6 hours) | Once established, water deeply every 2–3 weeks in summer; no supplemental water needed once the taproot is mature | Pet-safe |
| Roundleaf Pickerelweed | Direct sun (at least 4-6 hours) | Permanently aquatic — plant in still or slow-moving water 5–20 cm (2–8 in) deep or in consistently waterlogged marginal soil. | Pet-safe |
| Roundleaf Sundew | Direct sun (at least 4-6 hours) | Keep saturated; stand in 1-3 cm of pure water through the growing season | Mildly toxic to pets |
| Rowallane quince | Bright indirect light (just back from a sunny window) | Weekly when establishing; every 2–3 weeks during dry spells once established | Mildly toxic to pets |
| Roxburgh's Begonia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost feels dry, roughly every 7-10 days in growth | Toxic to pets |
| Royal Azalea | Bright indirect light (just back from a sunny window) | Every 5-7 days in the growing season; reduce after leaf drop | Toxic to pets |
| Royal Blue Aubrieta | Direct sun (at least 4-6 hours) | Weekly in spring and autumn; infrequently in summer | Pet-safe |
| Royal Star Magnolia | Direct sun (at least 4-6 hours) | Weekly while young; in summer droughts for established shrubs | Pet-safe |
| Rubenza cosmos | Direct sun (at least 4-6 hours) | Every 5–7 days; drought tolerant once established | Pet-safe |
| Rubrum Epimedium | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry, roughly every 1-2 weeks | Mildly toxic to pets |
| Ruby Ribbons Switch Grass | Direct sun (at least 4-6 hours) | Weekly during establishment; afterwards only in drought | Mildly toxic to pets |
| Rudbeckia 'Autumn Colors' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Rudbeckia 'Becky Mixed' | Direct sun (at least 4-6 hours) | Every 7-10 days once established; keep containers evenly moist | Pet-safe |
| Rudbeckia 'Cherry Brandy' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Rudbeckia 'Denver Daisy' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Rudbeckia 'Goldsturm' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; roughly weekly in summer, more in prolonged heat | Mildly toxic to pets |
| Rudbeckia 'Goldsturm' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days; very drought-tolerant once established | Pet-safe |
| Rudbeckia 'Henry Eilers' | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 7-14 days | Mildly toxic to pets |
| Rudbeckia 'Indian Summer' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Rudbeckia 'Little Henry' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Rudbeckia 'Pot of Gold' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Rudbeckia 'Prairie Sun' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Rudbeckia 'Sahara' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Rudbeckia 'Toto Gold' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in containers | Mildly toxic to pets |
| Rudbeckia maxima | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about weekly until established | Mildly toxic to pets |
| Ruellia Brittoniana | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 5-10 days; very drought-tolerant once established | Mildly toxic to pets |
| Rufa Fountain Bamboo | Bright indirect light (just back from a sunny window) | Regularly during the growing season, approximately every 5–7 days; keep soil consistently moist but not waterlogged | Pet-safe |
| Rugosa Rose | Direct sun (at least 4-6 hours) | weekly when establishing, monthly once established | Pet-safe |
| Running Tapestry Foamflower | Medium indirect light (a couple of metres from a window) | Every 5–7 days; more during summer drought | Pet-safe |
| Running Tapestry Tiarella | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply once or twice weekly in dry spells | Mildly toxic to pets |
| Russell Lupin 'Band of Nobles' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Russian Arborvitae | Bright indirect light (just back from a sunny window) | Water weekly until established; drought-tolerant once mature | Mildly toxic to pets |
| Russian Olive | Direct sun (at least 4-6 hours) | Low; highly drought-tolerant | Pet-safe |
| Rustica Rubra magnolia | Direct sun (at least 4-6 hours) | Regularly when young; moderate once established | Pet-safe |
| Rusty Foxglove | Direct sun (at least 4-6 hours) | When the top few cm of soil are dry; established plants are fairly drought-tolerant | Toxic to pets |
| Sacchariflorus Silver Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; tolerates moist to wet soils thereafter | Mildly toxic to pets |
| Sagae Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Sage-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Deeply but infrequently once established; every 2–3 weeks in the first two summers, then rainfall alone suffices in most UK/mild US climates. | Mildly toxic to pets |
| Sagittaria latifolia | Direct sun (at least 4-6 hours) | Keep in shallow standing water year-round | Mildly toxic to pets |
| Sagittaria sagittifolia | Direct sun (at least 4-6 hours) | Keep in shallow standing water year-round | Mildly toxic to pets |
| Sahuc's Sun Rose Hybrid | Direct sun (at least 4-6 hours) | Infrequent once established | Mildly toxic to pets |
| Saintpaulia 'Buckeye Fanfare' | Bright indirect light (just back from a sunny window) | When the top of the mix is just dry, about every 5-7 days | Pet-safe |
| Saintpaulia 'Jolly Ellie' | Bright indirect light (just back from a sunny window) | When the surface of the mix is just dry, roughly every 5-7 days | Pet-safe |
| Saintpaulia 'Mac's Black Pearl' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil feels dry, roughly every 5-7 days | Pet-safe |
| Saintpaulia 'Ness' Dipity' | Bright indirect light (just back from a sunny window) | When the top of the mix is just dry to the touch, about every 5-7 days | Pet-safe |
| Saintpaulia 'Optimara Montana' | Bright indirect light (just back from a sunny window) | When the surface of the mix is just dry, roughly every 5-7 days | Pet-safe |
| Saintpaulia 'Powderpuff' | Bright indirect light (just back from a sunny window) | When the surface of the mix is just dry, roughly every 5-7 days | Pet-safe |
| Saintpaulia 'Rob's Boolaroo' | Bright indirect light (just back from a sunny window) | When the top of the mix feels just dry, typically every 5-7 days | Pet-safe |
| Saintpaulia 'Winter Lace' | Bright indirect light (just back from a sunny window) | When the top of the mix feels just dry, about every 5-7 days | Pet-safe |
| Sakhalin Fir | Direct sun (at least 4-6 hours) | Moderate; water regularly during establishment | Pet-safe |
| Salal | Low light (north window or shaded room) | Moderate; established plants are drought-tolerant but prefer moist conditions | Pet-safe |
| Sally Holmes Rose | Direct sun (at least 4-6 hours) | Deep watering once or twice weekly | Pet-safe |
| Sally-My-Handsome | Direct sun (at least 4-6 hours) | Every 3–4 weeks in the growing season; minimal in winter | Mildly toxic to pets |
| Salmon Queen scabiosa | Direct sun (at least 4-6 hours) | Every 5–7 days in active growth; reduce in cool spells | Pet-safe |
| Salvia | Direct sun (at least 4-6 hours) | Weekly watering | Pet-safe |
| Salvia 'Hot Lips' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; weekly while establishing, then infrequently | Pet-safe |
| Salvia 'May Night' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry; roughly weekly, less once established | Pet-safe |
| Salvia × sylvestris 'Blauhügel' | Direct sun (at least 4-6 hours) | When top 3-5 cm of soil is dry, roughly every 7-10 days once established | Pet-safe |
| Salvia farinacea 'Evolution Violet' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 4-7 days once established | Pet-safe |
| Salvia farinacea 'Strata' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 4-7 days once established | Pet-safe |
| Salvia nemorosa 'Ostfriesland' | Direct sun (at least 4-6 hours) | When top 3-5 cm of soil is dry, about every 7-10 days once established | Pet-safe |
| Salvia splendens 'Sizzler Burgundy' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-5 days | Mildly toxic to pets |
| Salvia splendens 'Vista Red' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer heat | Pet-safe |
| Salvia verticillata 'Purple Rain' | Direct sun (at least 4-6 hours) | When top 3-5 cm of soil is dry, about every 7-10 days once established | Pet-safe |
| Salvia yangii | Direct sun (at least 4-6 hours) | When top 5 cm of soil is dry, roughly every 10-14 days once established | Mildly toxic to pets |
| San Diego Sage | Direct sun (at least 4-6 hours) | Low; drought tolerant once established | Pet-safe |
| Sand Bluestem | Direct sun (at least 4-6 hours) | Minimal — seasonal rainfall only in most settings | Pet-safe |
| Sand Couch Grass | Direct sun (at least 4-6 hours) | Rarely — established plants rely on rainfall and groundwater | Pet-safe |
| Sand Crocus | Direct sun (at least 4-6 hours) | Water sparingly; keep dry in summer | Toxic to pets |
| Sand Everlasting | Direct sun (at least 4-6 hours) | Every 2–4 weeks; minimal in winter | Mildly toxic to pets |
| Sand Lovegrass | Direct sun (at least 4-6 hours) | When the top 4-6 cm of soil is dry, roughly every 10-14 days | Pet-safe |
| Sand Phlox | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; drought-tolerant | Pet-safe |
| Sand Pink | Direct sun (at least 4-6 hours) | Low; water only when soil is completely dry, roughly every 2–3 weeks in the growing season | Mildly toxic to pets |
| Sand Reed | Direct sun (at least 4-6 hours) | Rarely — depends on deep soil moisture in sand | Pet-safe |
| Sand Sedge | Direct sun (at least 4-6 hours) | Very infrequent — drought-adapted | Pet-safe |
| Sander's Vanda | Direct sun (at least 4-6 hours) | Daily in warmth; every 2-3 days when cool and dim | Pet-safe |
| Sanders Blue Spruce | Direct sun (at least 4-6 hours) | Keep evenly moist; water deeply weekly while establishing, then during dry periods | Mildly toxic to pets |
| Sandpaper verbena | Direct sun (at least 4-6 hours) | Every 5–7 days once established; more frequently in extreme heat | Mildly toxic to pets |
| Sanguine Coneflower | Direct sun (at least 4-6 hours) | Weekly during first season; every 3–4 weeks once established | Pet-safe |
| Sanguisorba 'Tanna' | Direct sun (at least 4-6 hours) | Keep soil moist but not waterlogged; water every 4-7 days in dry weather | Pet-safe |
| Sanguisorba canadensis | Direct sun (at least 4-6 hours) | Keep consistently moist; water 2-3 times weekly in dry spells | Mildly toxic to pets |
| Sanguisorba menziesii | Direct sun (at least 4-6 hours) | Keep soil moist; water every 3-5 days in dry spells | Pet-safe |
| Sanguisorba obtusa | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply once or twice a week in dry spells | Mildly toxic to pets |
| Sanguisorba officinalis | Direct sun (at least 4-6 hours) | Keep soil moist; water every 4-7 days in dry spells | Pet-safe |
| Santa Barbara Ceanothus | Direct sun (at least 4-6 hours) | Every 7-10 days during the first growing season; established plants are very drought-tolerant and need watering only during prolonged drought | Mildly toxic to pets |
| Santa Rita Prickly Pear | Direct sun (at least 4-6 hours) | Sparingly when soil is fully dry, about every 3-4 weeks in summer; nearly none in winter | Pet-safe |
| Sanvitalia procumbens 'Mandarin Orange' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 2-4 days in summer containers | Pet-safe |
| Sanvitalia procumbens 'Sunvy Yellow' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 2-4 days in summer containers | Pet-safe |
| Saphyr Rouge Firethorn | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Sapphire Blue Oat Grass | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing, then occasionally | Mildly toxic to pets |
| Sapphire Tower | Direct sun (at least 4-6 hours) | every 7–10 days in the growing season, every 21–28 days in winter | Pet-safe |
| Sarcococca confusa | Low light (north window or shaded room) | Water regularly to establish; afterwards every 7-14 days during dry spells | Mildly toxic to pets |
| Sarcococca Humilis | Low light (north window or shaded room) | Water regularly to establish; thereafter every 7-14 days in prolonged dry spells | Mildly toxic to pets |
| Sardinian Glory of the Snow | Bright indirect light (just back from a sunny window) | Low; natural rainfall sufficient in most temperate climates | Mildly toxic to pets |
| Sardinian Glory of the Snow | Bright indirect light (just back from a sunny window) | Relies on natural rainfall during spring; water only if conditions are exceptionally dry | Toxic to pets |
| Sargent Cherry Bonsai | Direct sun (at least 4-6 hours) | When the top 2 cm of soil starts to dry, often daily in summer | Toxic to pets |
| Sargent's quince | Bright indirect light (just back from a sunny window) | Weekly when establishing; drought-tolerant once established | Mildly toxic to pets |
| Sarracenia 'Juthatip Soper' | Direct sun (at least 4-6 hours) | Keep permanently wet with the tray method, standing in 1-3 cm of water during the growing season | Pet-safe |
| Sarracenia × catesbaei | Direct sun (at least 4-6 hours) | Keep media constantly wet; stand the pot in 1-2 cm of water during the growing season | Pet-safe |
| Sarracenia × excellens | Direct sun (at least 4-6 hours) | Permanently moist; tray-water in 1-2 cm of pure water through the growing season | Pet-safe |
| Sarracenia flava var. ornata | Direct sun (at least 4-6 hours) | Keep constantly wet, standing in 1-3 cm of water through the growing season | Mildly toxic to pets |
| Sarracenia leucophylla 'Tarnok' | Direct sun (at least 4-6 hours) | Keep constantly wet; stand in 1-2 cm of pure water during the growing season | Pet-safe |
| Sarracenia oreophila | Direct sun (at least 4-6 hours) | Keep soil constantly wet; stand in 1-3 cm of water during the growing season | Mildly toxic to pets |
| Sarracenia purpurea subsp. venosa | Direct sun (at least 4-6 hours) | Keep permanently moist to standing in 1-3 cm of water; never let the bog dry out | Mildly toxic to pets |
| Sasanqua Camellia | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water deeply once or twice weekly in the growing season, more in heat | Pet-safe |
| Sasanqua Camellia 'Yuletide' | Bright indirect light (just back from a sunny window) | About weekly, more in summer heat; water when the top 3-5 cm of soil is dry | Pet-safe |
| Satomi Dogwood | Bright indirect light (just back from a sunny window) | Weekly during the growing season; every 2 weeks once fully established | Mildly toxic to pets |
| Satsuki Azalea | Bright indirect light (just back from a sunny window) | Keep evenly moist — water when the surface just begins to dry, often daily in heat | Toxic to pets |
| Saucer Magnolia | Direct sun (at least 4-6 hours) | Weekly while establishing, then during dry spells | Pet-safe |
| Saucer Magnolia | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 10–14 days once mature in dry spells | Pet-safe |
| Savin Juniper | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; weekly during the first growing season | Toxic to pets |
| Saw-wort | Bright indirect light (just back from a sunny window) | Low once established | Mildly toxic to pets |
| Sawara Cypress | Direct sun (at least 4-6 hours) | When the top 2 cm of soil starts to dry, often daily in summer heat | Mildly toxic to pets |
| Sawtooth Sunflower | Direct sun (at least 4-6 hours) | Weekly when young; every 1-2 weeks when established | Pet-safe |
| Scabiosa columbaria 'Butterfly Blue' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil dries; about weekly in the growing season | Pet-safe |
| Scabrosa Rugosa Rose | Direct sun (at least 4-6 hours) | Weekly while establishing; drought-tolerant afterwards | Pet-safe |
| Scaevola aemula 'Bombay Dark Blue' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm is dry, roughly every 3-5 days | Mildly toxic to pets |
| Scaevola aemula 'Whirlwind White' | Direct sun (at least 4-6 hours) | Water when the top 2-3 cm dries; baskets often need it every 1-3 days | Mildly toxic to pets |
| Scaly Blazing Star | Direct sun (at least 4-6 hours) | Water to establish, then only in prolonged drought | Pet-safe |
| Scaly Male Fern | Low light (north window or shaded room) | Keep soil moist; water in dry spells, especially while establishing | Mildly toxic to pets |
| Scarlet Ball Cactus | Direct sun (at least 4-6 hours) | When the mix is dry, about every 10-14 days in growth; sparingly in winter | Pet-safe |
| Scarlet Ball Cactus | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is dry, every 7-10 days in spring and summer; every 3-5 weeks in autumn; very sparingly in winter | Pet-safe |
| Scarlet Bee Balm | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; often twice weekly in summer heat | Mildly toxic to pets |
| Scarlet Bidi-Bidi | Direct sun (at least 4-6 hours) | Fortnightly once established; drought-tolerant | Pet-safe |
| Scarlet bugler | Direct sun (at least 4-6 hours) | Every 10–14 days once established; minimal supplemental water needed | Mildly toxic to pets |
| Scarlet Dahlia | Direct sun (at least 4-6 hours) | 2–3 times per week during active growth | Mildly toxic to pets |
| Scarlet Freesia | Direct sun (at least 4-6 hours) | Low to moderate during active growth; dry during summer dormancy | Pet-safe |
| Scarlet Giant Hyssop | Direct sun (at least 4-6 hours) | Every 7–10 days until established; every 14 days or less once established | Pet-safe |
| Scarlet Leucothoe | Medium indirect light (a couple of metres from a window) | Regular; maintain consistent moisture | Toxic to pets |
| Scarlet Martagon Lily | Direct sun (at least 4-6 hours) | Moderate — water when top 5 cm of soil is dry | Toxic to pets |
| Scarlet Monkeyflower | Bright indirect light (just back from a sunny window) | Constantly moist to wet — water every 1–2 days in summer | Mildly toxic to pets |
| Scarlet Passion Flower | Direct sun (at least 4-6 hours) | When the top 2 cm of soil is dry, roughly every 5-8 days in summer | Mildly toxic to pets |
| Scarlet Sage | Direct sun (at least 4-6 hours) | Every 3–5 days; keep evenly moist | Mildly toxic to pets |
| Scarletta Leucothoe | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season; do not allow soil to dry | Toxic to pets |
| Scepter'd Isle Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season; more in heat, sandy soil or containers | Pet-safe |
| Schizanthus pinnatus 'Angel Wings' | Bright indirect light (just back from a sunny window) | When the top 2 cm of soil is just drying, roughly every 3-5 days | Mildly toxic to pets |
| Schlumbergera 'White Christmas' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days in growth | Pet-safe |
| Schlumbergera × buckleyi | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Schoenoplectus tabernaemontani 'Albescens' | Direct sun (at least 4-6 hours) | Keep permanently wet; never let the crown dry out | Mildly toxic to pets |
| Schoenoplectus tabernaemontani 'Zebrinus' | Direct sun (at least 4-6 hours) | Constantly wet; shallow margin | Mildly toxic to pets |
| Sciadopitys 'Ossorio Gold' | Bright indirect light (just back from a sunny window) | Keep evenly moist; deep weekly watering while establishing, more during heat or drought | Mildly toxic to pets |
| Sciadopitys 'Wintergreen' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water deeply weekly in the first 2-3 years, more in heat | Mildly toxic to pets |
| Scilla siberica | Direct sun (at least 4-6 hours) | Rainfall in most settings; rarely needs watering | Mildly toxic to pets |
| Scirpus lacustris | Direct sun (at least 4-6 hours) | Constantly wet; shallow to moderately deep water | Mildly toxic to pets |
| Scots Pine | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil begins to dry, every few days in summer | Mildly toxic to pets |
| Scottish Heath | Bright indirect light (just back from a sunny window) | Moderate — water during dry spells | Mildly toxic to pets |
| Sea Bindweed | Direct sun (at least 4-6 hours) | Sparingly; rely on rainfall in a well-drained coastal setting | Mildly toxic to pets |
| Sea Campion | Direct sun (at least 4-6 hours) | Every 1–2 weeks; drought-tolerant once established | Pet-safe |
| Sea Heath | Direct sun (at least 4-6 hours) | Very low; drought-tolerant once established | Mildly toxic to pets |
| Sea Holly | Direct sun (at least 4-6 hours) | Water occasionally while establishing, then rarely once mature | Mildly toxic to pets |
| Sea Knotgrass | Direct sun (at least 4-6 hours) | Very low; exceptionally drought-tolerant | Mildly toxic to pets |
| Sea Mouse-ear | Direct sun (at least 4-6 hours) | Minimal; rely on rainfall in outdoor settings | Mildly toxic to pets |
| Sea Pea | Direct sun (at least 4-6 hours) | Infrequently; allow soil to dry between waterings | Toxic to pets |
| Sea Purslane Sun Rose | Direct sun (at least 4-6 hours) | Very low — drought-tolerant once established; water sparingly in the first year only | Mildly toxic to pets |
| Sea Sandwort | Direct sun (at least 4-6 hours) | Infrequently — allow soil to dry between waterings | Pet-safe |
| Sea Spurge | Direct sun (at least 4-6 hours) | Sparingly — very drought-tolerant | Toxic to pets |
| Sea Stock | Direct sun (at least 4-6 hours) | Weekly during active growth (allow surface to dry slightly between waterings) | Pet-safe |
| Sea Stork's Bill | Direct sun (at least 4-6 hours) | Water sparingly; this species is adapted to dry, free-draining coastal soils | Mildly toxic to pets |
| Sea Thrift | Direct sun (at least 4-6 hours) | Every 10–14 days; drought-tolerant once established | Pet-safe |
| Sea Urchin Cactus | Direct sun (at least 4-6 hours) | When the top of the soil is dry, roughly weekly to fortnightly in summer; keep nearly dry in winter | Pet-safe |
| Seabeach Sandwort | Direct sun (at least 4-6 hours) | Infrequently — highly drought-tolerant once established | Pet-safe |
| Sedum 'Autumn Joy' | Direct sun (at least 4-6 hours) | When soil is dry several centimeters down, roughly every 10-14 days | Pet-safe |
| Sedum 'Matrona' | Direct sun (at least 4-6 hours) | When soil is dry a few centimeters down, roughly every 10-14 days | Pet-safe |
| Sedum spectabile 'Iceberg' | Direct sun (at least 4-6 hours) | When soil is dry a few centimeters down, about every 10-14 days | Pet-safe |
| Sedum telephium 'Purple Emperor' | Direct sun (at least 4-6 hours) | When soil is dry a few centimeters down, about every 10-14 days | Pet-safe |
| Seigen Japanese Maple | Bright indirect light (just back from a sunny window) | Keep evenly moist; often daily through summer | Mildly toxic to pets |
| Selenicereus pteranthus | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-14 days in summer | Pet-safe |
| Sellow's Sinningia | Bright indirect light (just back from a sunny window) | Moderate during growth; none during dormancy | Pet-safe |
| Sensation Mix Cosmos | Direct sun (at least 4-6 hours) | When the top 3–5 cm of soil is dry, roughly every 7–10 days once established | Pet-safe |
| Sensation Mixed cosmos | Direct sun (at least 4-6 hours) | Once or twice weekly until established; then only during prolonged dry spells | Pet-safe |
| Sensation Mixed cosmos | Direct sun (at least 4-6 hours) | Every 5–7 days; very drought tolerant once established | Pet-safe |
| Sequoia 'Adpressa' | Bright indirect light (just back from a sunny window) | When the top few centimetres of soil dry; keep consistently moist, every 5-10 days | Mildly toxic to pets |
| Serbian Spruce | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing in the first two years; established trees rely on rainfall except in prolonged drought | Mildly toxic to pets |
| Serbian Spruce 'Pendula' | Direct sun (at least 4-6 hours) | Every 7-10 days for the first two years; thereafter mostly rainfall-dependent except in drought | Mildly toxic to pets |
| Serrated Enkianthus | Bright indirect light (just back from a sunny window) | Regular — even moisture throughout growing season | Toxic to pets |
| Sesse's Sage | Direct sun (at least 4-6 hours) | Every 7–10 days in summer; monthly in winter | Mildly toxic to pets |
| Sessile Bellwort | Medium indirect light (a couple of metres from a window) | Moderate; keep soil moist in spring and early summer. Tolerates periodic dryness once established. | Pet-safe |
| Sessile Oak | Direct sun (at least 4-6 hours) | Rainfall-dependent once established; water deeply during the first 2–3 years | Mildly toxic to pets |
| Sessile-Leaf Tick Trefoil | Bright indirect light (just back from a sunny window) | Water every 10–14 days during establishment; once established it is drought-tolerant in typical dry woodland and upland conditions | Pet-safe |
| Sessile-leaved Bellwort | Medium indirect light (a couple of metres from a window) | Once or twice per week during the growing season; minimal watering needed once the plant enters summer dormancy. | Mildly toxic to pets |
| Sexy Rexy Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly | Pet-safe |
| Shadscale Saltbush | Direct sun (at least 4-6 hours) | Every 3–5 weeks during establishment, then rainfall only | Pet-safe |
| Shady Sage | Bright indirect light (just back from a sunny window) | Allow soil to dry between waterings | Pet-safe |
| Shagbark manzanita | Direct sun (at least 4-6 hours) | Every 3–4 weeks once established; more frequent during the first 2 years | Pet-safe |
| Shallon | Medium indirect light (a couple of metres from a window) | Moderate; drought-tolerant once established | Mildly toxic to pets |
| Sharp-fruited Abutilon | Direct sun (at least 4-6 hours) | Every 7–10 days when young; fortnightly once established | Pet-safe |
| Sharp-lobed Hepatica | Medium indirect light (a couple of metres from a window) | Every 5–7 days in spring; reduced to every 10–14 days in summer | Mildly toxic to pets |
| Shasta daisy | Direct sun (at least 4-6 hours) | Every 5–7 days in summer; less frequently once established | Mildly toxic to pets |
| Sheep Laurel | Bright indirect light (just back from a sunny window) | Regular; keep soil consistently moist | Toxic to pets |
| sheep's fescue | Direct sun (at least 4-6 hours) | Very low; once established, relies on natural rainfall in temperate climates; water monthly if needed during prolonged drought | Pet-safe |
| Sheep's Fescue | Direct sun (at least 4-6 hours) | Established plants are very drought-tolerant; water only during severe prolonged drought, roughly every 14-21 days in dry conditions | Pet-safe |
| Sheerwater Seedling rowan | Direct sun (at least 4-6 hours) | Regular through spring and summer for the first 2 years; minimal once established | Mildly toxic to pets |
| Shenandoah Switch Grass | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water deeply every 1-2 weeks while young | Mildly toxic to pets |
| Shenandoah Switchgrass | Direct sun (at least 4-6 hours) | Weekly during establishment (first season); monthly or as needed once established | Pet-safe |
| Sheridan Spire Dawn Redwood | Direct sun (at least 4-6 hours) | Regularly — maintain consistently moist soil | Pet-safe |
| Shimpaku Juniper | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is just dry, often daily in summer heat | Toxic to pets |
| Shingle Oak | Direct sun (at least 4-6 hours) | Moderate; weekly irrigation for first 2 seasons; drought-tolerant once established | Mildly toxic to pets |
| Shining Cinquefoil | Direct sun (at least 4-6 hours) | Every 10–14 days during active growth; very sparsely in winter | Pet-safe |
| Shining Cranesbill | Bright indirect light (just back from a sunny window) | Low; water only in prolonged drought | Pet-safe |
| Shining fetterbush | Bright indirect light (just back from a sunny window) | Consistently moist to wet — do not allow prolonged drought | Toxic to pets |
| Shining Pondweed | Direct sun (at least 4-6 hours) | Fully submerged — permanently aquatic; water is the growing medium, not an irrigation schedule | Pet-safe |
| Shining Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in growth; greatly reduced to near-dry during dormancy | Mildly toxic to pets |
| Shining Temple Bells | Medium indirect light (a couple of metres from a window) | Every 3–4 days during active growth; none during winter dormancy | Mildly toxic to pets |
| Shohin Japanese Maple | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; often daily in summer heat | Mildly toxic to pets |
| Shooting Star Hoya | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-9 days in growth | Pet-safe |
| Shore Juniper | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; regular watering for first 12 months | Mildly toxic to pets |
| Shore Pine | Direct sun (at least 4-6 hours) | When the top 2-3 cm of the mix is dry, often daily in summer heat and every 3-5 days in cool weather | Pet-safe |
| Short-Sepalled Lewisia | Direct sun (at least 4-6 hours) | Moderate in spring; bone-dry in summer dormancy | Mildly toxic to pets |
| Showy Autumn Crocus | Bright indirect light (just back from a sunny window) | Relies on natural rainfall when established; no summer irrigation | Toxic to pets |
| Showy Autumn Crocus | Bright indirect light (just back from a sunny window) | Relies on natural rainfall; rarely needs supplementary watering in the garden | Toxic to pets |
| Showy Border Forsythia | Direct sun (at least 4-6 hours) | Every 7-14 days during dry spells; very drought-tolerant once established | Pet-safe |
| Showy Cranesbill | Bright indirect light (just back from a sunny window) | Weekly during spring and summer; minimal in autumn and winter | Pet-safe |
| Showy Disocactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, approximately every 7-10 days in spring and summer; reduce to every 3-4 weeks in winter | Pet-safe |
| Showy Goldenrod | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water in extended dry spells only | Pet-safe |
| Showy Japanese Lily | Bright indirect light (just back from a sunny window) | When top 2–3 cm of soil is dry | Toxic to pets |
| Showy Milkweed | Direct sun (at least 4-6 hours) | Water weekly the first season; once established water deeply only during prolonged drought | Toxic to pets |
| Showy Sinningia | Bright indirect light (just back from a sunny window) | Keep soil slightly moist during growth; dry off in autumn | Pet-safe |
| Showy Stonecrop | Direct sun (at least 4-6 hours) | Every 1–2 weeks in dry spells; drought-tolerant once established | Mildly toxic to pets |
| Showy Tick Trefoil | Direct sun (at least 4-6 hours) | Water weekly to every 10 days during dry spells in the first season; once established, tolerates moderate drought but prefers consistently moist soil | Pet-safe |
| Shrimp Plant | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil feels dry, roughly weekly in summer | Mildly toxic to pets |
| Shrubby Indian Mallow | Direct sun (at least 4-6 hours) | Every 10–14 days in summer; monthly or as needed in winter | Pet-safe |
| Shrubby Nemesia | Direct sun (at least 4-6 hours) | Water when the top 2–3 cm of soil is dry | Mildly toxic to pets |
| Shrubby St John's Wort | Bright indirect light (just back from a sunny window) | Drought-tolerant once established; water through the first season | Toxic to pets |
| Shrubby St. John's Wort | Direct sun (at least 4-6 hours) | Once a week during establishment; drought-tolerant once established | Mildly toxic to pets |
| Siberian Bugloss 'Hadspen Cream' | Medium indirect light (a couple of metres from a window) | Every 5-7 days during the growing season; reduce in winter | Pet-safe |
| Siberian Carpet Cypress | Medium indirect light (a couple of metres from a window) | Moderate — once established, largely drought-tolerant | Mildly toxic to pets |
| Siberian dogwood | Bright indirect light (just back from a sunny window) | Weekly when establishing; tolerates wet conditions long-term | Mildly toxic to pets |
| Siberian Elm Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil dries, typically daily in summer | Mildly toxic to pets |
| Siberian Fir | Direct sun (at least 4-6 hours) | Moderate; relies on snowmelt and seasonal rain | Pet-safe |
| Siberian Iris | Direct sun (at least 4-6 hours) | Regular — keep soil consistently moist | Toxic to pets |
| Siberian Lady Fern | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water when the top 2 cm begin to dry, roughly weekly in dry weather | Mildly toxic to pets |
| Siberian Larch | Direct sun (at least 4-6 hours) | Weekly during establishment; low once established | Pet-safe |
| Siberian larkspur | Direct sun (at least 4-6 hours) | Regular — water 2–3 times per week; reduce to weekly once established in cool weather | Toxic to pets |
| Siberian Mountain Heath | Bright indirect light (just back from a sunny window) | Water regularly to keep soil evenly and consistently moist; never allow to dry out. | Mildly toxic to pets |
| Sibthorp's Everlasting | Direct sun (at least 4-6 hours) | Every 2–3 weeks in growing season; sparingly in winter | Mildly toxic to pets |
| Sichuan Arborvitae | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Sickle-leaved Hare's-ear | Direct sun (at least 4-6 hours) | Every 10–14 days, allowing soil to dry between waterings | Mildly toxic to pets |
| Side Oats Grama | Direct sun (at least 4-6 hours) | Water to establish, then only in extreme drought | Mildly toxic to pets |
| Sidebells Beardtongue | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; monthly in cool or dormant seasons | Mildly toxic to pets |
| Sidebells Penstemon | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; monthly in cool seasons | Mildly toxic to pets |
| Sieber's Crocus | Direct sun (at least 4-6 hours) | Low — water at planting, then rely on rainfall during active growth; keep dry in summer dormancy | Mildly toxic to pets |
| Sieber's Crocus | Direct sun (at least 4-6 hours) | Rainfall typically sufficient; supplement with light watering weekly only during prolonged dry spells in the growing season | Mildly toxic to pets |
| Siebold's Magnolia | Bright indirect light (just back from a sunny window) | Weekly throughout the growing season; reduce in winter | Pet-safe |
| Sierra Juniper | Direct sun (at least 4-6 hours) | When the soil has begun to dry; lean toward the dry side | Mildly toxic to pets |
| Sierra laurel | Medium indirect light (a couple of metres from a window) | Frequently; keep consistently moist | Toxic to pets |
| Sierra Leucothoe | Medium indirect light (a couple of metres from a window) | Regularly; do not allow to dry out between waterings | Toxic to pets |
| Signet marigold | Direct sun (at least 4-6 hours) | Once or twice weekly; allow top 2 cm of soil to dry between waterings | Mildly toxic to pets |
| Signet Marigold 'Lemon Gem' | Direct sun (at least 4-6 hours) | When top 2-3 cm of soil is dry, every 4-7 days; containers more often | Mildly toxic to pets |
| Sikkim Larch | Direct sun (at least 4-6 hours) | Weekly during establishment, less once established | Pet-safe |
| Silberfeder Silver Feather Grass | Direct sun (at least 4-6 hours) | Weekly through the first season, then only in extended drought | Mildly toxic to pets |
| Silky Aster | Direct sun (at least 4-6 hours) | Low — drought tolerant | Pet-safe |
| Silky Lupine | Direct sun (at least 4-6 hours) | Low; deeply water every 2–3 weeks during the growing season; minimal water once dormant | Toxic to pets |
| Silky Prairie Clover | Direct sun (at least 4-6 hours) | Very low — highly drought-tolerant; avoid overwatering | Mildly toxic to pets |
| silky thread grass | Direct sun (at least 4-6 hours) | Once established, water only during extended drought; every 2–3 weeks in hot, dry summers | Pet-safe |
| Silky wisteria | Direct sun (at least 4-6 hours) | Weekly during growing season; reduce in winter | Toxic to pets |
| Silver Cup Annual Mallow | Direct sun (at least 4-6 hours) | When the top 3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Silver Feather Grass | Direct sun (at least 4-6 hours) | Water every 7-14 days during the first growing season; established clumps require little supplemental watering | Mildly toxic to pets |
| Silver Fir | Direct sun (at least 4-6 hours) | Weekly during establishment; rainfall-dependent once established | Pet-safe |
| Silver Knight heather | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate watering once established | Pet-safe |
| Silver Light Bergenia | Medium indirect light (a couple of metres from a window) | Every 7–10 days in the growing season; reduce in autumn and winter | Pet-safe |
| Silver Mound Artemisia | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; roughly every 7-10 days while establishing, then rarely | Toxic to pets |
| Silver Mullein | Direct sun (at least 4-6 hours) | Every 2–4 weeks when established; weekly for young transplants | Mildly toxic to pets |
| Silver Pagoda Dogwood | Bright indirect light (just back from a sunny window) | Regular throughout the growing season; do not allow to dry out | Mildly toxic to pets |
| Silver Pink Rock Rose | Direct sun (at least 4-6 hours) | Establish with regular watering in the first season; once established, water only during prolonged drought spells in summer. | Mildly toxic to pets |
| Silver Ragwort | Direct sun (at least 4-6 hours) | low — allow soil to dry between waterings | Toxic to pets |
| Silver Sage | Direct sun (at least 4-6 hours) | Fortnightly or when soil is dry | Pet-safe |
| Silver Shamrock | Direct sun (at least 4-6 hours) | Water sparingly; allow to dry between waterings | Toxic to pets |
| silver spike grass | Direct sun (at least 4-6 hours) | Weekly in the first season; monthly deep watering once established | Pet-safe |
| Silver Tansy | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; more frequent only when young | Mildly toxic to pets |
| Silver Vase Bromeliad | Bright indirect light (just back from a sunny window) | Keep the central cup filled with soft water; water potting medium only when it approaches dryness | Pet-safe |
| Silver-edged Primrose | Bright indirect light (just back from a sunny window) | Every 5–7 days in active growth; reduce in summer dormancy | Mildly toxic to pets |
| Silver-leaf Sinningia | Bright indirect light (just back from a sunny window) | Every 10–14 days in the growing season; water very sparingly or not at all during dormancy | Pet-safe |
| Silverberry | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Pet-safe |
| Silverbush | Direct sun (at least 4-6 hours) | Moderate in the growing season, minimal in winter | Mildly toxic to pets |
| Silvery Lupine | Direct sun (at least 4-6 hours) | Low to moderate; water deeply every 2–3 weeks during the growing season; drought-tolerant once established | Toxic to pets |
| Silvery Yarrow | Direct sun (at least 4-6 hours) | Every 10–14 days; very drought-tolerant once established | Mildly toxic to pets |
| Simple-leaf astilbe | Medium indirect light (a couple of metres from a window) | Consistently moist — water 2–3 times per week in dry spells | Pet-safe |
| Sinaloa Sage | Bright indirect light (just back from a sunny window) | Weekly in the growing season; allow soil to partially dry between waterings | Mildly toxic to pets |
| Single-Flowered Bladderwort | Bright indirect light (just back from a sunny window) | Keep substrate permanently moist to wet throughout the growing season; reduce to just damp in cooler winter months | Mildly toxic to pets |
| Single-leaf Cape Primrose | Bright indirect light (just back from a sunny window) | every 7–10 days in the growing season, reduce to every 14–21 days in winter | Pet-safe |
| Sinningia 'Duchess of York' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days in growth | Pet-safe |
| Sinningia 'Empress' | Bright indirect light (just back from a sunny window) | When the top 1-2 cm of soil is dry, keeping the mix evenly moist during active growth | Pet-safe |
| Sinningia 'Li'l Georgie' | Bright indirect light (just back from a sunny window) | When the top 1 cm of soil is dry, about every 4-7 days | Pet-safe |
| Sinningia 'Prudence Risley' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Pet-safe |
| Sinningia concinna | Bright indirect light (just back from a sunny window) | Keep evenly lightly moist while in growth, watering when the surface just dries, roughly every 5-8 days | Pet-safe |
| Sinningia eumorpha | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Pet-safe |
| Sinningia tubiflora | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Pet-safe |
| Sinomiyama Toad Lily | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water when the surface begins to dry, often twice weekly in summer | Mildly toxic to pets |
| Sintenis's Rock Rose | Direct sun (at least 4-6 hours) | Deeply once or twice monthly during the first growing season; essentially rain-fed once established in the ground. | Mildly toxic to pets |
| sioux blue indian grass | Direct sun (at least 4-6 hours) | Regularly during first season; once established, water only during prolonged summer drought | Pet-safe |
| Siskiyou Blue Idaho Fescue | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; deep but infrequent once established | Mildly toxic to pets |
| Siskiyou Lewisia | Bright indirect light (just back from a sunny window) | Regular in spring/summer; very sparing in winter | Mildly toxic to pets |
| Sissinghurst White Pulmonaria | Low light (north window or shaded room) | Keep soil evenly moist; water every 4-6 days in dry weather, more in containers | Mildly toxic to pets |
| Sitka Spruce | Direct sun (at least 4-6 hours) | Regular — keep soil consistently moist; very high natural rainfall in native habitat | Pet-safe |
| Six Hills Giant Catmint | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; about every 7-10 days while establishing, then seldom | Mildly toxic to pets |
| Skimmia japonica Kew White | Medium indirect light (a couple of metres from a window) | Maintain consistently moist soil; water deeply every 5-7 days in dry weather | Mildly toxic to pets |
| Skimmia japonica Rubella | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water deeply every 5-7 days in dry spells, less in cool months | Mildly toxic to pets |
| Skimmia Pabella | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water deeply every 5-7 days in dry spells | Mildly toxic to pets |
| Skimmia Temptation | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water deeply every 5-7 days during dry periods | Mildly toxic to pets |
| Skinners Achimenes | Bright indirect light (just back from a sunny window) | Consistently moist throughout the growing season; dry during winter dormancy | Pet-safe |
| Sky Blue Aster | Direct sun (at least 4-6 hours) | Water to establish, then rarely; very drought-tolerant | Pet-safe |
| Sky Lupine | Direct sun (at least 4-6 hours) | Low; winter rainfall sufficient in most California climates; light supplemental water in February–March extends bloom | Toxic to pets |
| Sky Rocket Feather Top | Direct sun (at least 4-6 hours) | Weekly while establishing, then occasional deep watering in drought | Pet-safe |
| Skyracer Moor Grass | Direct sun (at least 4-6 hours) | Regular; maintain consistent moisture | Pet-safe |
| Skyrocket Juniper | Direct sun (at least 4-6 hours) | Every 7-10 days when establishing, then occasional deep soaks | Mildly toxic to pets |
| Sleeping Beauty Cymbidium | Bright indirect light (just back from a sunny window) | Every 5–7 days during active growth; reduce to every 10–14 days in autumn–winter | Pet-safe |
| Slender Aubrieta | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Mildly toxic to pets |
| Slender Begonia | Bright indirect light (just back from a sunny window) | When the top 2 cm of compost feel dry | Toxic to pets |
| Slender Silhouette Sweetgum | Direct sun (at least 4-6 hours) | Weekly during the first 2–3 years; supplemental in drought once established | Mildly toxic to pets |
| Slim-leaved Biarum | Direct sun (at least 4-6 hours) | Water sparingly in autumn and winter; keep completely dry from late spring through summer dormancy | Toxic to pets |
| Slipper Flower | Bright indirect light (just back from a sunny window) | Regularly — keep soil evenly moist, especially in bud and bloom | Mildly toxic to pets |
| Slowmound Mugo Pine | Direct sun (at least 4-6 hours) | Water weekly through the first growing season, then only during extended drought | Mildly toxic to pets |
| Small Cape Primrose | Medium indirect light (a couple of metres from a window) | every 7–10 days in the growing season, every 14–21 days in winter | Pet-safe |
| Small Grape Hyacinth | Direct sun (at least 4-6 hours) | Rainfall usually sufficient; water once per week only if spring is unusually dry | Toxic to pets |
| Small Japanese Silver Grass | Bright indirect light (just back from a sunny window) | Weekly during the first season; every 10–14 days once established, or as needed during drought. | Mildly toxic to pets |
| Small Scabious | Direct sun (at least 4-6 hours) | Moderate while establishing; reduced once rooted — water when the top few centimetres of soil are dry | Mildly toxic to pets |
| Small Solomon's Seal | Low light (north window or shaded room) | Every 5-7 days in active growth; drought-tolerant once established | Toxic to pets |
| Small Teasel | Medium indirect light (a couple of metres from a window) | Regular; keep soil reliably moist | Mildly toxic to pets |
| Small-flowered alumroot | Medium indirect light (a couple of metres from a window) | Weekly during the growing season; do not allow to dry out completely | Pet-safe |
| Small-flowered calibrachoa | Direct sun (at least 4-6 hours) | Every 2–3 days in warm weather; weekly when established or in cool periods | Mildly toxic to pets |
| Small-flowered Cape Primrose | Medium indirect light (a couple of metres from a window) | Every 7-10 days in active growth; every 3 weeks in winter | Pet-safe |
| Small-Flowered Cranesbill | Bright indirect light (just back from a sunny window) | Low; water sparingly and only in drought | Pet-safe |
| Small-flowered Pickerelweed | Direct sun (at least 4-6 hours) | Continuously moist to submerged | Pet-safe |
| Small-Flowered Rock Rose | Direct sun (at least 4-6 hours) | Low — establishment watering only | Mildly toxic to pets |
| Small-leaved Fuchsia | Bright indirect light (just back from a sunny window) | Every 5-7 days in the growing season; every 14-21 days in winter | Pet-safe |
| Small-scaled Pink | Direct sun (at least 4-6 hours) | Low to moderate; allow soil to approach dryness between waterings | Mildly toxic to pets |
| Small's Beardtongue | Bright indirect light (just back from a sunny window) | Every 1–2 weeks; reduce in winter | Pet-safe |
| Smith's Fairybells | Medium indirect light (a couple of metres from a window) | Weekly during the growing season; reduce in winter dormancy | Mildly toxic to pets |
| Smokebush 'Royal Purple' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry; weekly in the first season, then only in extended drought | Mildly toxic to pets |
| Smooth Arizona Cypress | Direct sun (at least 4-6 hours) | Infrequently; highly drought-tolerant once established | Mildly toxic to pets |
| Smooth Beardtongue | Bright indirect light (just back from a sunny window) | Weekly to every 10 days; adapts to both drought and periodic wet | Pet-safe |
| Smooth Blue Aster | Direct sun (at least 4-6 hours) | Water weekly until established, then sparingly | Pet-safe |
| Smooth Coneflower | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| Smooth Cordgrass | Direct sun (at least 4-6 hours) | Continuous tidal immersion — lower intertidal zone | Pet-safe |
| Smooth Hydrangea 'Incrediball' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, often every 2-4 days in summer | Toxic to pets |
| Smooth Oxeye | Direct sun (at least 4-6 hours) | Every 1-2 weeks | Pet-safe |
| Smooth Phlox | Bright indirect light (just back from a sunny window) | 2–3 times per week in summer; weekly when established | Pet-safe |
| Smooth Solomon's Seal | Medium indirect light (a couple of metres from a window) | Regular; keep soil evenly moist | Mildly toxic to pets |
| Snake Cactus | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days in summer; every 3-4 weeks in winter | Pet-safe |
| Snake Orchid | Bright indirect light (just back from a sunny window) | Keep evenly moist, about every 4-6 days in growth, drier in winter | Pet-safe |
| Snake's Head Iris | Direct sun (at least 4-6 hours) | Moderate in autumn to spring; dry in summer | Toxic to pets |
| Snapdragon | Direct sun (at least 4-6 hours) | Weekly watering | Pet-safe |
| Snapdragon 'Madame Butterfly' | Direct sun (at least 4-6 hours) | Keep evenly moist; water about twice a week, adjusting for heat, letting the top of the soil dry first | Pet-safe |
| Snapdragon 'Rocket' | Direct sun (at least 4-6 hours) | Keep evenly moist; water roughly twice a week, more in heat, letting the surface dry between | Pet-safe |
| Snapdragon Achimenes | Bright indirect light (just back from a sunny window) | Keep evenly moist during the growing season (spring–autumn); withhold entirely during winter dormancy | Pet-safe |
| Snapdragon vine | Bright indirect light (just back from a sunny window) | Water when the top 2–3 cm of soil dries out, roughly every 5–7 days | Pet-safe |
| Sneezeweed | Direct sun (at least 4-6 hours) | Keep consistently moist; water every 4-7 days, more in heat | Toxic to pets |
| Sneezeweed 'Moerheim Beauty' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Sneezeweed 'Riverton Beauty' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days during the growing season | Toxic to pets |
| Sneezewort | Direct sun (at least 4-6 hours) | Weekly or more in dry spells; tolerates seasonal moisture | Mildly toxic to pets |
| Snow Crystals Sweet Alyssum | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil feels dry, roughly every 5-7 days in warm weather | Pet-safe |
| Snow Trillium | Medium indirect light (a couple of metres from a window) | Moderate during spring growth; dry summer dormancy | Mildly toxic to pets |
| Snow-in-Summer | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season; minimal in winter | Pet-safe |
| snowball bush | Bright indirect light (just back from a sunny window) | Weekly when young; every 1–2 weeks once established | Mildly toxic to pets |
| Snowberry | Bright indirect light (just back from a sunny window) | Regular; keep consistently moist | Mildly toxic to pets |
| Snowberry Creeper | Bright indirect light (just back from a sunny window) | Every 5–7 days; keep soil consistently moist but never waterlogged | Mildly toxic to pets |
| Snowberry Heath | Medium indirect light (a couple of metres from a window) | Regularly; maintain consistently moist but not waterlogged soil | Pet-safe |
| Snowdrop Windflower | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| Snowy Wood Rush | Bright indirect light (just back from a sunny window) | Moderate; water every 7–10 days in dry periods, more frequently in summer heat | Pet-safe |
| Snowy Woodrush | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season | Pet-safe |
| Socotra Begonia | Bright indirect light (just back from a sunny window) | Every 7–10 days during the growing season (autumn–spring); completely dry during summer dormancy | Toxic to pets |
| Soft Draba | Direct sun (at least 4-6 hours) | Very low — keep almost dry in winter | Mildly toxic to pets |
| Soft-stem Bulrush | Direct sun (at least 4-6 hours) | Permanently aquatic or waterlogged; plant at 0–60 cm (0–24 in) water depth | Pet-safe |
| Solanum crispum 'Glasnevin' | Direct sun (at least 4-6 hours) | Keep evenly moist in the first two seasons; water established plants during prolonged dry spells | Toxic to pets |
| Solanum laxum | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-10 days in growth | Toxic to pets |
| Solanum laxum 'Album' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-10 days in growth | Toxic to pets |
| Solidago 'Fireworks' | Direct sun (at least 4-6 hours) | Water weekly until established, then only in droughts | Mildly toxic to pets |
| Solomon's Seal | Low light (north window or shaded room) | Every 5-7 days in active growth; less frequent once established | Toxic to pets |
| Sophy's Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in growth; container plants checked more often | Pet-safe |
| Sorbet XP Mix Viola | Bright indirect light (just back from a sunny window) | When the top 1–2 cm of soil begins to dry, roughly every 4–6 days | Mildly toxic to pets |
| Sorbus 'Joseph Rock' | Direct sun (at least 4-6 hours) | Water weekly for the first two seasons; established trees need water only in extended drought | Mildly toxic to pets |
| Sorbus aria | Direct sun (at least 4-6 hours) | Water weekly in the first two growing seasons; established trees are markedly drought-tolerant | Mildly toxic to pets |
| Sorbus hupehensis | Direct sun (at least 4-6 hours) | Water weekly through the first two seasons; established trees are fairly drought-tolerant | Mildly toxic to pets |
| Southern Cattail | Direct sun (at least 4-6 hours) | Continuously moist to submerged | Pet-safe |
| Southern Heath | Direct sun (at least 4-6 hours) | Water regularly but allow the soil surface to dry slightly between waterings | Pet-safe |
| Southern Japanese Hemlock | Bright indirect light (just back from a sunny window) | Weekly during the growing season; reduced in winter | Pet-safe |
| Southern Magnolia | Direct sun (at least 4-6 hours) | Deeply once a week for the first two seasons; established trees need water only in drought | Pet-safe |
| Southern Magnolia 'Little Gem' | Direct sun (at least 4-6 hours) | Weekly deep watering while establishing, then every 1-2 weeks in dry weather | Pet-safe |
| Southern Marsh Orchid | Direct sun (at least 4-6 hours) | Consistently moist to wet | Mildly toxic to pets |
| Southern Red Trillium | Medium indirect light (a couple of metres from a window) | Regularly moist in spring; reduce by mid-summer | Mildly toxic to pets |
| Southern Shield Fern | Bright indirect light (just back from a sunny window) | Water when the top 3-4 cm of soil dries out, roughly every 5-10 days in summer; reduce in winter | Mildly toxic to pets |
| Souvenir de la Malmaison Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly while establishing; mature plants when the top 5 cm of soil is dry | Pet-safe |
| Spanish Bluebell | Medium indirect light (a couple of metres from a window) | Low to moderate; largely self-sufficient once established | Toxic to pets |
| Spanish Draba | Direct sun (at least 4-6 hours) | Water sparingly; allow soil to dry between waterings | Pet-safe |
| Spanish Fir | Direct sun (at least 4-6 hours) | Every 1–2 weeks during establishment; minimal once mature | Pet-safe |
| Spanish Gorse | Direct sun (at least 4-6 hours) | Low — water only to establish; drought-tolerant thereafter | Toxic to pets |
| Spanish heath | Direct sun (at least 4-6 hours) | Weekly during establishment; fortnightly in summer once established | Pet-safe |
| Spanish Iris | Direct sun (at least 4-6 hours) | Low to moderate — water during growth; keep dry in summer | Toxic to pets |
| Spanish Juniper | Direct sun (at least 4-6 hours) | Water fortnightly when young; essentially self-sufficient once established | Mildly toxic to pets |
| Spanish love-in-a-mist | Direct sun (at least 4-6 hours) | Weekly during dry periods | Mildly toxic to pets |
| Spanish snapdragon | Direct sun (at least 4-6 hours) | Once established, every 7–14 days in summer; rarely in winter | Mildly toxic to pets |
| Spanish Stonecrop | Direct sun (at least 4-6 hours) | Low — drought-tolerant; water only in very dry spells | Pet-safe |
| Sparganium erectum | Direct sun (at least 4-6 hours) | Constantly wet; shallow water or saturated margin | Mildly toxic to pets |
| Spatterdock | Direct sun (at least 4-6 hours) | Permanently aquatic; plant at 30–120 cm (12–48 in) water depth | Mildly toxic to pets |
| Spatulate Dendrobium | Bright indirect light (just back from a sunny window) | Regularly through warm growth; reduced over a cool, brighter winter rest | Pet-safe |
| Spencer Mixed sweet pea | Direct sun (at least 4-6 hours) | Every 5–7 days; keep roots evenly moist | Mildly toxic to pets |
| Spencer Waved sweet pea | Direct sun (at least 4-6 hours) | Every 2–4 days in warm weather; every 5–7 days in cool spells | Toxic to pets |
| Spider Iris | Direct sun (at least 4-6 hours) | Moderate in winter growing season; bone dry in summer dormancy | Toxic to pets |
| Spider Milkweed | Direct sun (at least 4-6 hours) | Low; deep watering every 2–4 weeks once established | Toxic to pets |
| Spider Orchid | Bright indirect light (just back from a sunny window) | When the bark surface dries, roughly every 5-7 days in growth | Mildly toxic to pets |
| Spider Orchid (Brassia) | Bright indirect light (just back from a sunny window) | Roughly weekly in growth; let the bark nearly dry between waterings | Mildly toxic to pets |
| Spike heath | Direct sun (at least 4-6 hours) | Low to moderate — once established, water only during prolonged drought | Pet-safe |
| spiked sedge | Bright indirect light (just back from a sunny window) | Moderate; water weekly in dry spells once established | Pet-safe |
| Spiked speedwell | Direct sun (at least 4-6 hours) | Every 7–14 days; drought-tolerant once established | Pet-safe |
| Spiny Fuchsia | Direct sun (at least 4-6 hours) | Infrequent — allow soil to dry between waterings | Pet-safe |
| Spiny Germander | Direct sun (at least 4-6 hours) | Very infrequently once established; water lightly only during extreme summer drought | Mildly toxic to pets |
| Spiraea 'Anthony Waterer' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Spiraea 'Gold Flame' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about once per week | Mildly toxic to pets |
| Spiraea 'Goldflame' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during active growth | Mildly toxic to pets |
| Spiraea 'Grefsheim' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Spiraea 'Little Princess' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about once per week | Mildly toxic to pets |
| Spiraea 'Little Princess' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Spiraea 'Magic Carpet' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Spiraea 'Shirobana' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days once established | Pet-safe |
| Spiraea betulifolia 'Tor' | Direct sun (at least 4-6 hours) | Weekly when young; during dry spells only once established | Mildly toxic to pets |
| Spiraea nipponica 'Snowmound' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, about once per week | Mildly toxic to pets |
| Spiraea prunifolia | Direct sun (at least 4-6 hours) | Weekly while establishing; only in extended dry spells once mature | Mildly toxic to pets |
| Spiraea thunbergii 'Ogon' | Direct sun (at least 4-6 hours) | Weekly while establishing, then only in droughts | Mildly toxic to pets |
| Spiraea x vanhouttei | Direct sun (at least 4-6 hours) | Weekly in the first year; established plants need water only in prolonged drought | Mildly toxic to pets |
| Splitbeard Bluestem | Direct sun (at least 4-6 hours) | When the top 4-5 cm of soil is dry, roughly every 10-14 days | Pet-safe |
| Spotted Corn Lily | Direct sun (at least 4-6 hours) | Moderate in growth; completely dry in summer dormancy | Mildly toxic to pets |
| Spotted Dead Nettle | Medium indirect light (a couple of metres from a window) | Every 5–7 days in active growth; reduce to every 10–14 days in cool or dormant periods | Pet-safe |
| Spotted Joe Pye Weed | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water weekly or more in dry spells | Pet-safe |
| Spotted Mandarin | Medium indirect light (a couple of metres from a window) | Regular; keep soil evenly moist | Mildly toxic to pets |
| Spotted Nomocharis | Bright indirect light (just back from a sunny window) | Moderate to high; soil should remain consistently moist | Toxic to pets |
| Spotted Sinningia | Bright indirect light (just back from a sunny window) | Every 7–10 days in growth; withhold almost entirely during dormancy | Mildly toxic to pets |
| Spotted Trillium | Medium indirect light (a couple of metres from a window) | Regular during active growth; minimal when dormant | Mildly toxic to pets |
| Spottted Horsemint | Direct sun (at least 4-6 hours) | Water to establish, then only in prolonged drought, roughly every 10-14 days | Mildly toxic to pets |
| Spreading Achimenes | Bright indirect light (just back from a sunny window) | Evenly moist during the growing season; completely dry during winter rhizome dormancy | Pet-safe |
| Spreading Bellflower | Direct sun (at least 4-6 hours) | Low — water only during prolonged dry spells | Pet-safe |
| Sprenger's Tulip | Bright indirect light (just back from a sunny window) | Water during growth; dry in summer | Toxic to pets |
| Spring Beauty | Medium indirect light (a couple of metres from a window) | Moderate during active growth (February–May); none needed during summer dormancy. | Pet-safe |
| Spring Cinquefoil | Direct sun (at least 4-6 hours) | Rarely once established; drought-tolerant | Pet-safe |
| Spring Cinquefoil (Potentilla tabernaemontani) | Direct sun (at least 4-6 hours) | Rarely; drought-tolerant once established | Pet-safe |
| Spring Cream heather | Direct sun (at least 4-6 hours) | Weekly during establishment; less frequent once established | Pet-safe |
| Spring Cyclamen | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry during active growth (autumn through spring); withhold during summer dormancy | Toxic to pets |
| Spring Cyclamen | Medium indirect light (a couple of metres from a window) | When the top 2 cm of soil is dry, roughly every 7-10 days during active growth | Toxic to pets |
| Spring Gentian | Direct sun (at least 4-6 hours) | Regular; keep soil evenly moist, never waterlogged | Mildly toxic to pets |
| Spring Meadow Saffron | Direct sun (at least 4-6 hours) | Rainfall-dependent through winter and spring; dry summer rest | Toxic to pets |
| Spring Snowflake | Medium indirect light (a couple of metres from a window) | Regularly during growth (late winter–spring); reduced but not dry in summer | Toxic to pets |
| Spring Starflower | Bright indirect light (just back from a sunny window) | Occasional in autumn and spring; dry during summer dormancy | Toxic to pets |
| Spring Symphony Foamflower | Medium indirect light (a couple of metres from a window) | Approximately every 5–7 days; more frequently in heat or drought | Pet-safe |
| Spring Symphony Tiarella | Medium indirect light (a couple of metres from a window) | Keep consistently moist; deep-water once or twice weekly during dry weather | Mildly toxic to pets |
| Springwood White winter heath | Direct sun (at least 4-6 hours) | Weekly for new plantings; established plants tolerate dry spells with watering every 2–3 weeks | Pet-safe |
| Square-stalked St John's-wort | Bright indirect light (just back from a sunny window) | High — keep consistently moist to wet | Toxic to pets |
| Square-stemmed Pelargonium | Direct sun (at least 4-6 hours) | Water very sparingly — every 14-21 days in the growing season; almost none in winter | Toxic to pets |
| Squinancywort | Direct sun (at least 4-6 hours) | Rarely — only during prolonged drought | Mildly toxic to pets |
| Squirrel Corn | Medium indirect light (a couple of metres from a window) | Every 3-5 days in spring growing season; no irrigation once dormant | Toxic to pets |
| St Dabeoc's heath | Direct sun (at least 4-6 hours) | Moderate; water regularly to keep soil evenly moist, especially in the first year | Pet-safe |
| Stachyurus praecox | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil begins to dry, roughly every 5-7 days in summer for younger plants | Mildly toxic to pets |
| Staggerbush | Bright indirect light (just back from a sunny window) | Regularly — keep soil consistently moist, especially in the first 2 years | Toxic to pets |
| Standish's Golden Yew | Direct sun (at least 4-6 hours) | Moderate — once established, rarely needs irrigation in UK climates | Toxic to pets |
| Standishii Yew | Bright indirect light (just back from a sunny window) | When the top 5 cm of soil is dry, about weekly while establishing | Toxic to pets |
| Stanhopea tigrina | Bright indirect light (just back from a sunny window) | Every 2-4 days in warm active growth; weekly in cooler, shorter days | Pet-safe |
| Star Jasmine | Bright indirect light (just back from a sunny window) | Water regularly to establish; once mature, water during dry spells when the top few cm of soil dries | Pet-safe |
| Star Magnolia | Direct sun (at least 4-6 hours) | Keep moist while establishing; water deeply weekly in dry spells for the first few years | Pet-safe |
| Star Magnolia 'Royal Star' | Direct sun (at least 4-6 hours) | Weekly while young, then in dry periods | Pet-safe |
| Star of Bethlehem | Direct sun (at least 4-6 hours) | Infrequent; relies on natural rainfall in most temperate gardens | Toxic to pets |
| Star of Bethlehem | Bright indirect light (just back from a sunny window) | Relies on natural rainfall; supplement only during extended dry spells in spring | Toxic to pets |
| Star of Bethlehem Orchid | Bright indirect light (just back from a sunny window) | When the bark approaches dryness, roughly every 4-7 days | Pet-safe |
| Star-flowered Solomon's Seal | Medium indirect light (a couple of metres from a window) | 2 times per week during the growing season; reduce in dormancy | Mildly toxic to pets |
| Stardust Ice Plant | Direct sun (at least 4-6 hours) | Every 1–2 weeks during active growth; very sparingly in winter | Pet-safe |
| Stardust Ice Plant | Direct sun (at least 4-6 hours) | When the top 3 cm of soil is dry, roughly every 7–14 days in summer; reduce in autumn and maintain nearly dry in winter | Mildly toxic to pets |
| Starflower | Medium indirect light (a couple of metres from a window) | Regular; keep soil consistently moist throughout the growing season (spring through autumn). | Pet-safe |
| Starflower pincushion | Direct sun (at least 4-6 hours) | Every 6–8 days during active growth | Pet-safe |
| Starina Miniature Rose | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 2-4 days in summer | Pet-safe |
| Starry Rosinweed | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Mildly toxic to pets |
| Starry Solomon's Seal | Medium indirect light (a couple of metres from a window) | Regular, keeping soil evenly moist | Mildly toxic to pets |
| Statice | Direct sun (at least 4-6 hours) | Low to moderate — allow soil to dry between waterings | Pet-safe |
| Statice sea lavender | Direct sun (at least 4-6 hours) | Once weekly; allow the top 2–3 cm of soil to dry between waterings | Pet-safe |
| Steeds Japanese Holly | Direct sun (at least 4-6 hours) | Weekly deep watering while establishing, then every 7-14 days during dry spells | Toxic to pets |
| Stem-forming Torch Lily | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days during the growing season | Mildly toxic to pets |
| Stemless African Daisy | Direct sun (at least 4-6 hours) | Every 10–14 days (moderate); reduce in dry periods once established | Mildly toxic to pets |
| Stemless Gentian | Bright indirect light (just back from a sunny window) | Regular, keeping soil evenly moist throughout the growing season | Mildly toxic to pets |
| Stemless Thistle | Direct sun (at least 4-6 hours) | Very low — fully drought tolerant | Mildly toxic to pets |
| Steppe Sage | Direct sun (at least 4-6 hours) | Low — every 10–14 days in summer, minimal in winter | Mildly toxic to pets |
| Sterling Silver Linden | Direct sun (at least 4-6 hours) | Weekly during the first 2 years; monthly deep watering once established | Pet-safe |
| Stewartia monadelpha | Bright indirect light (just back from a sunny window) | Weekly; keep soil consistently moist but well-drained | Pet-safe |
| Stewartia pseudocamellia | Bright indirect light (just back from a sunny window) | Weekly; keep soil consistently moist but never waterlogged | Pet-safe |
| Sticky Jerusalem Sage | Direct sun (at least 4-6 hours) | Once every 2 weeks in summer; suspend watering October–March except in prolonged drought | Mildly toxic to pets |
| Sticky Primrose | Bright indirect light (just back from a sunny window) | Regularly in spring and summer; minimal in winter | Toxic to pets |
| Stiff Goldenrod | Direct sun (at least 4-6 hours) | Highly drought-tolerant; water only in prolonged drought | Pet-safe |
| Stiff Sunflower | Direct sun (at least 4-6 hours) | Every 2-3 weeks once established | Pet-safe |
| Stiff twinspur | Direct sun (at least 4-6 hours) | 2–3 times per week in active growth; once per week when established in cooler weather | Pet-safe |
| Stinking Iris | Low light (north window or shaded room) | Low to moderate — drought-tolerant once established | Toxic to pets |
| Stinking Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist to damp through the growing season; reduce after summer dormancy | Mildly toxic to pets |
| Stock | Direct sun (at least 4-6 hours) | Every 5–7 days; keep evenly moist but not wet | Pet-safe |
| Stoloniferous Sundew | Bright indirect light (just back from a sunny window) | Tray method during winter growing season; completely dry during summer dormancy | Mildly toxic to pets |
| Stonecrop 'Autumn Joy' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is fully dry, roughly every 10-14 days; less frequent once established | Pet-safe |
| Stonecrop 'Dragon's Blood' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is completely dry, roughly every 10-14 days; minimal once established | Pet-safe |
| Strachey's Bergenia | Medium indirect light (a couple of metres from a window) | Every 7–10 days during the growing season; reduce in winter | Pet-safe |
| Stratiotes aloides | Direct sun (at least 4-6 hours) | Submerged to surface-floating; keep in still water 0.3-1.5 m deep | Mildly toxic to pets |
| Straw Foxglove | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about weekly in dry weather | Toxic to pets |
| Straw-red Sage | Direct sun (at least 4-6 hours) | Every 10–14 days once established; weekly for new plants | Pet-safe |
| Strawberries and Cream Ribbon Grass | Bright indirect light (just back from a sunny window) | Adaptable; moist soil gives best colour but tolerates drought once established | Mildly toxic to pets |
| Strawberry Fields gomphrena | Direct sun (at least 4-6 hours) | Weekly; drought-tolerant once established | Pet-safe |
| Strawberry Foxglove | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water weekly in dry periods | Toxic to pets |
| Strawberry Foxglove | Bright indirect light (just back from a sunny window) | Once or twice a week in dry periods; consistent moisture prolongs flowering | Toxic to pets |
| Strawberry globe amaranth | Direct sun (at least 4-6 hours) | Every 7–14 days once established; moderate during establishment | Pet-safe |
| Strawflower | Direct sun (at least 4-6 hours) | Every 7–10 days; very drought-tolerant | Mildly toxic to pets |
| Streambank Lupine | Bright indirect light (just back from a sunny window) | Moderate; keep soil evenly moist; tolerates periodic wet conditions unlike most lupines | Toxic to pets |
| Streptocarpus 'Bethan' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Streptocarpus 'Black Panther' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Streptocarpus 'Chorus Line' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Streptocarpus 'Falling Stars' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Streptocarpus 'Harlequin Blue' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 7-10 days | Pet-safe |
| Streptocarpus 'Polka-Dot Purple' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Streptocarpus 'Purple Haze' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil feels dry, about every 7-10 days | Pet-safe |
| Streptocarpus 'Targa' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, around every 7-10 days | Pet-safe |
| Streptocarpus caulescens | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 7-12 days | Pet-safe |
| Streptocarpus saxorum | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 7-12 days | Pet-safe |
| Stribrny's Saxifrage | Direct sun (at least 4-6 hours) | Water sparingly; keep almost dry in winter | Mildly toxic to pets |
| Stricta Feather Reed Grass | Direct sun (at least 4-6 hours) | Consistently moist; tolerates standing water in spring | Pet-safe |
| Strictus Porcupine Grass | Direct sun (at least 4-6 hours) | Weekly to establish, then during dry spells; benefits from steady moisture | Mildly toxic to pets |
| Stripe It Rich Hakone Grass | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Striped Amaryllis | Bright indirect light (just back from a sunny window) | Sparingly when first potted; increase as the flower stalk emerges; water every 7–10 days during active growth; withhold during dormancy | Toxic to pets |
| Striped Squill | Bright indirect light (just back from a sunny window) | Regular during growth; dry when dormant | Mildly toxic to pets |
| Striptease Hosta | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in growth | Toxic to pets |
| Strobilanthes kunthianus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 4-7 days in the growing season | Mildly toxic to pets |
| Subalpine Fir | Direct sun (at least 4-6 hours) | Regular watering during establishment; naturally sustained by snowmelt and high-altitude precipitation | Pet-safe |
| Subalpine Larch | Direct sun (at least 4-6 hours) | Moderate; supplemental irrigation during dry summers | Pet-safe |
| Sublime Slipper Orchid | Medium indirect light (a couple of metres from a window) | When the top of the mix is just barely drying, roughly every 5-7 days | Mildly toxic to pets |
| Sugar and Spice Tiarella | Medium indirect light (a couple of metres from a window) | Keep consistently moist; deep-water once or twice weekly in dry spells | Mildly toxic to pets |
| Sugarcane Plume Grass | Direct sun (at least 4-6 hours) | Keep evenly moist; water weekly in dry spells, more in containers | Mildly toxic to pets |
| Sukhakul's Slipper Orchid | Medium indirect light (a couple of metres from a window) | When the surface of the mix starts to dry, roughly every 5-7 days | Pet-safe |
| Sullivant's Milkweed | Direct sun (at least 4-6 hours) | Regular; maintain consistent moisture | Toxic to pets |
| Sulphur Clover | Bright indirect light (just back from a sunny window) | Low to moderate; drought-tolerant once established | Pet-safe |
| Sulphur Cosmos | Direct sun (at least 4-6 hours) | Water until established, then only in extended drought; highly drought-tolerant | Pet-safe |
| Sulphureum Epimedium | Medium indirect light (a couple of metres from a window) | When the top 3-4 cm of soil is dry, roughly every 1-2 weeks | Mildly toxic to pets |
| Summer Hyacinth | Direct sun (at least 4-6 hours) | Regular during spring and summer; reduce in autumn and winter | Pet-safe |
| Summer Skies delphinium | Direct sun (at least 4-6 hours) | Regular — deep water 2–3 times per week during growth; reduce to weekly after first bloom | Toxic to pets |
| Summer Snowflake | Bright indirect light (just back from a sunny window) | Regularly during growth (spring); tolerates seasonal dryness once dormant | Toxic to pets |
| Summer Wave Amethyst Wishbone Flower | Medium indirect light (a couple of metres from a window) | When the top 2 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Summit Sage | Bright indirect light (just back from a sunny window) | Every 10–14 days | Pet-safe |
| Sun Flare Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly | Pet-safe |
| Sunblaze Miniature Rose | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 2-4 days in summer | Pet-safe |
| Sunflower | Direct sun (at least 4-6 hours) | Deep watering once a week | Pet-safe |
| Sungold Cypress | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water deeply weekly in the first 2 years, then every 10-14 days in dry spells | Toxic to pets |
| Sunningdale Silver Pampas Grass | Direct sun (at least 4-6 hours) | Weekly while establishing; thereafter only in extended drought | Pet-safe |
| Sunrise Crown Cactus | Direct sun (at least 4-6 hours) | When fully dry, roughly every 12-16 days in growth; none in winter | Pet-safe |
| Sunsatia Mango Nemesia | Direct sun (at least 4-6 hours) | When the top 2-3 cm of compost is dry, roughly every 4-6 days | Pet-safe |
| Sunsatia Plus Coconut Nemesia | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil or compost is dry, roughly every 4-6 days | Pet-safe |
| Sunset Hyssop | Direct sun (at least 4-6 hours) | Every 7–10 days once established | Pet-safe |
| Superb pink | Direct sun (at least 4-6 hours) | Every 7–10 days; drought-tolerant once established | Mildly toxic to pets |
| Superba Astilbe | Bright indirect light (just back from a sunny window) | Keep soil moist; water when the top 2-3 cm dries, roughly every 4-6 days in summer | Mildly toxic to pets |
| Superba Pubescent Lilac | Direct sun (at least 4-6 hours) | When the top 5 cm of soil feels dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Superba Rodgersia | Medium indirect light (a couple of metres from a window) | Keep consistently moist; water deeply 1-2 times weekly, more in heat | Mildly toxic to pets |
| Supertunia 'Vista Bubblegum' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry; daily in hot weather and containers | Pet-safe |
| Supertunia bubblegum petunia | Direct sun (at least 4-6 hours) | Every 2–4 days in containers in heat; every 5–7 days in borders | Pet-safe |
| Susan Magnolia | Direct sun (at least 4-6 hours) | Weekly during establishment (2–3 years); every 10–14 days when mature in dry weather | Mildly toxic to pets |
| Swamp Azalea | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; in garden settings water every 5-7 days during dry spells | Toxic to pets |
| Swamp doghobble | Medium indirect light (a couple of metres from a window) | Frequently; keep soil consistently moist | Toxic to pets |
| Swamp Loosestrife | Bright indirect light (just back from a sunny window) | Continuously — requires saturated soil or shallow water | Mildly toxic to pets |
| Swamp Milkweed | Direct sun (at least 4-6 hours) | Keep consistently moist; water during dry spells and never let it dry out for long | Toxic to pets |
| Swamp Rose Mallow | Direct sun (at least 4-6 hours) | Frequently; keep soil moist, tolerates wet conditions | Mildly toxic to pets |
| Swamp Rose Mallow | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water every 3-5 days in summer or more frequently in containers | Pet-safe |
| Swamp Sunflower | Direct sun (at least 4-6 hours) | Consistently moist; water weekly or more in dry periods | Pet-safe |
| Swamp Tupelo | Direct sun (at least 4-6 hours) | Constantly moist to permanently flooded | Mildly toxic to pets |
| Sweet alyssum | Bright indirect light (just back from a sunny window) | Every 5–7 days; drought-tolerant once established | Pet-safe |
| Sweet Autumn Clematis | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days once established | Toxic to pets |
| Sweet Autumn Clematis | Direct sun (at least 4-6 hours) | Deeply once a week during the growing season; drought-tolerant once established | Toxic to pets |
| Sweet Azalea | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in the growing season | Toxic to pets |
| Sweet Betsy | Medium indirect light (a couple of metres from a window) | Consistently moist through spring and early summer; reduced moisture acceptable during summer dormancy. | Mildly toxic to pets |
| Sweet Birch | Direct sun (at least 4-6 hours) | Moderate; water deeply during drought; established trees on suitable sites are largely self-sufficient | Pet-safe |
| Sweet Black-Eyed Susan | Direct sun (at least 4-6 hours) | Weekly in the first growing season; every 10–14 days when established | Pet-safe |
| Sweet Box | Low light (north window or shaded room) | Water regularly while establishing; once settled, every 7-14 days in dry spells | Mildly toxic to pets |
| Sweet Chariot Miniature Rose | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, often every 1-3 days in baskets during summer | Pet-safe |
| Sweet Clockvine | Direct sun (at least 4-6 hours) | Every 5–7 days; allow the top soil to partially dry between waterings | Mildly toxic to pets |
| Sweet Mock Orange | Bright indirect light (just back from a sunny window) | When the top 5 cm of soil feels dry, roughly every 7-14 days | Mildly toxic to pets |
| Sweet pea | Direct sun (at least 4-6 hours) | Weekly deep watering | Toxic to pets |
| Sweet Pea 'Cupani' | Direct sun (at least 4-6 hours) | Every 2-3 days in growth, more in heat; keep soil evenly moist | Mildly toxic to pets |
| Sweet Pea 'Spencer' | Direct sun (at least 4-6 hours) | Every 2-3 days, keeping soil consistently moist | Mildly toxic to pets |
| Sweet sultan | Direct sun (at least 4-6 hours) | Every 7–10 days | Pet-safe |
| Sweet Trillium | Low light (north window or shaded room) | Keep soil consistently moist spring through early summer; minimal once dormant | Mildly toxic to pets |
| Sweet violet | Medium indirect light (a couple of metres from a window) | Every 5–7 days; keep evenly moist | Pet-safe |
| Sweet White Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist during spring; reduce after dormancy onset | Mildly toxic to pets |
| Sweet White Violet | Medium indirect light (a couple of metres from a window) | Regular; keep soil consistently moist | Pet-safe |
| Sweet William | Direct sun (at least 4-6 hours) | Every 5–7 days; allow surface to dry slightly between waterings | Mildly toxic to pets |
| Sweetbay Magnolia | Direct sun (at least 4-6 hours) | Keep soil consistently moist; weekly deep watering when young and during dry spells | Pet-safe |
| Sweetbells Leucothoe | Medium indirect light (a couple of metres from a window) | Regularly throughout the growing season; do not allow to dry out | Toxic to pets |
| Sweetbriar Rose | Direct sun (at least 4-6 hours) | Weekly while establishing, then minimal | Pet-safe |
| Swiss Rock Jasmine | Direct sun (at least 4-6 hours) | Very sparingly year-round; almost dry in winter | Pet-safe |
| Sword-Leaved Phlox | Direct sun (at least 4-6 hours) | Weekly until established; monthly or less once established in well-drained soil | Pet-safe |
| Swordleaf Rush | Direct sun (at least 4-6 hours) | Consistently moist to wet soil; tolerates shallow standing water to 5 cm (2 in) | Pet-safe |
| Sycamore Maple | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water young trees weekly for the first 2 years | Toxic to pets |
| Symphyotrichum laeve 'Bluebird' | Direct sun (at least 4-6 hours) | Water to establish, then only in prolonged dry spells once settled | Pet-safe |
| Symphyotrichum novae-angliae 'Andenken an Alma Pötschke' | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water deeply in dry spells, roughly weekly | Pet-safe |
| Symphyotrichum novi-belgii 'Fellowship' | Direct sun (at least 4-6 hours) | Keep soil reliably moist; water deeply, around weekly, never letting roots dry | Pet-safe |
| Symphyotrichum oblongifolium 'Raydon's Favorite' | Direct sun (at least 4-6 hours) | Weekly during the first season; once established, only in prolonged drought | Pet-safe |
| Tagetes erecta 'Inca Gold' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-4 days | Pet-safe |
| Tagetes erecta 'Taishan Orange' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-4 days | Pet-safe |
| Tagetes patula 'Boy Orange' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-5 days | Pet-safe |
| Tagetes patula 'Janie Bright Yellow' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 3-5 days | Pet-safe |
| Tagetes tenuifolia 'Tangerine Gem' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Pet-safe |
| Tall Bluebells | Bright indirect light (just back from a sunny window) | Water deeply 2–3 times weekly; never allow to dry out in growing season | Pet-safe |
| Tall Coreopsis | Direct sun (at least 4-6 hours) | Low once established; water weekly during the first growing season | Pet-safe |
| Tall Goldenrod | Direct sun (at least 4-6 hours) | Drought-tolerant once established; water only in extended dry spells | Pet-safe |
| Tall Green Milkweed | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Toxic to pets |
| Tall Ironweed | Direct sun (at least 4-6 hours) | Keep evenly moist; water weekly in dry spells, more in heat | Mildly toxic to pets |
| Tall Mix pincushion flower | Direct sun (at least 4-6 hours) | Once or twice weekly | Pet-safe |
| Tall Moor Grass | Bright indirect light (just back from a sunny window) | Regular; keep soil evenly moist | Pet-safe |
| tall purple moor grass | Bright indirect light (just back from a sunny window) | Regularly during establishment; once established, water only in prolonged dry spells | Pet-safe |
| Tall Verbena | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-14 days once established | Mildly toxic to pets |
| Tamarack | Direct sun (at least 4-6 hours) | Regular; tolerates seasonally wet or boggy conditions | Pet-safe |
| Tangerine Beauty Crossvine | Bright indirect light (just back from a sunny window) | Weekly until established; drought-tolerant thereafter | Mildly toxic to pets |
| Tannenbaum Mugo Pine | Direct sun (at least 4-6 hours) | Water weekly the first year to establish, then during prolonged dry spells only | Mildly toxic to pets |
| Tartarian Honeysuckle | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days once established | Toxic to pets |
| Tasmanian Pernettya | Medium indirect light (a couple of metres from a window) | Regular; keep soil evenly moist | Mildly toxic to pets |
| Tassel Grape Hyacinth | Direct sun (at least 4-6 hours) | Minimal; drought-tolerant once established | Toxic to pets |
| Tassel Grape Hyacinth | Direct sun (at least 4-6 hours) | Once per week during spring growth; very dry during summer dormancy | Toxic to pets |
| Tattoo Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil is dry, about every 5-7 days during active growth | Toxic to pets |
| Tea Tree Bonsai | Direct sun (at least 4-6 hours) | Keep evenly moist; water when the surface just begins to dry, often every 1-3 days in summer | Mildly toxic to pets |
| Teasing Georgia Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season; more in heat | Pet-safe |
| Teddy Bear sunflower | Direct sun (at least 4-6 hours) | Weekly, or every 5–7 days during dry spells | Pet-safe |
| Tellmann's honeysuckle | Medium indirect light (a couple of metres from a window) | Weekly during dry spells; especially important in summer while in active growth | Mildly toxic to pets |
| Telstar Mix China Pink | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 5-7 days | Toxic to pets |
| Tenby Daffodil | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry during active growth, roughly every 7-10 days | Toxic to pets |
| Tennessee Coneflower | Direct sun (at least 4-6 hours) | Water to establish, then only during extended drought | Pet-safe |
| Tessellated Colchicum | Direct sun (at least 4-6 hours) | Minimal; water lightly after planting, then rely on rainfall during autumn–spring growth | Toxic to pets |
| Tessellated Vanda | Direct sun (at least 4-6 hours) | Daily in heat; every 2-3 days in cool, low-light spells | Pet-safe |
| Tetragona Aurea Hinoki Cypress | Direct sun (at least 4-6 hours) | Every 5-7 days when young, then when the top few cm of soil dry | Mildly toxic to pets |
| Texas Blazing Star | Direct sun (at least 4-6 hours) | Every 2–3 weeks during establishment; minimal once established | Pet-safe |
| Texas Bluebonnet | Direct sun (at least 4-6 hours) | Low; rely on rainfall; supplement only during prolonged dry spells in winter/spring | Toxic to pets |
| Texas Bluebonnet Subsp. | Direct sun (at least 4-6 hours) | Low; relies on autumn and winter rainfall; no regular supplemental watering needed once established | Toxic to pets |
| Texas Sage | Direct sun (at least 4-6 hours) | Moderate — water once or twice weekly in the growing season | Pet-safe |
| Thai Silk California poppy | Direct sun (at least 4-6 hours) | Once weekly during establishment; every 2 weeks once established | Mildly toxic to pets |
| Thai Silk Mix California Poppy | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days once established | Mildly toxic to pets |
| Thalictrum 'Elin' | Bright indirect light (just back from a sunny window) | Keep soil reliably moist; water deeply in dry spells | Mildly toxic to pets |
| Thalictrum aquilegiifolium | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water in dry spells | Mildly toxic to pets |
| Thalictrum delavayi 'Hewitt's Double' | Bright indirect light (just back from a sunny window) | Keep soil consistently moist; water regularly in dry weather, do not let it dry out | Mildly toxic to pets |
| Thalictrum flavum subsp. glaucum | Direct sun (at least 4-6 hours) | Keep soil moist; water deeply in dry weather | Mildly toxic to pets |
| Thalictrum rochebrunianum | Bright indirect light (just back from a sunny window) | About twice a week, keeping soil evenly moist | Toxic to pets |
| Thanksgiving Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 7-10 days | Pet-safe |
| The Blues Little Bluestem | Direct sun (at least 4-6 hours) | Every 2–3 weeks during the first growing season; minimal once established | Pet-safe |
| The Blues Little Bluestem | Direct sun (at least 4-6 hours) | Weekly for first season; every 3–4 weeks or rain-fed once established | Pet-safe |
| The Bride pearlbush | Direct sun (at least 4-6 hours) | Weekly during establishment; once established, every 2–3 weeks or during dry spells | Pet-safe |
| The Dark Lady Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly through the growing season, more in heat | Pet-safe |
| The Fairy Rose | Direct sun (at least 4-6 hours) | Deeply once a week in the growing season, more during heatwaves | Pet-safe |
| The Generous Gardener Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in growth; more during establishment and in heat | Pet-safe |
| The Governor lupine | Direct sun (at least 4-6 hours) | Every 7–10 days; less once established | Toxic to pets |
| The Pilgrim Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in growth; more in heat | Pet-safe |
| The Rocket Ligularia | Medium indirect light (a couple of metres from a window) | Keep soil constantly moist; water deeply 2-3 times weekly in summer, daily in heat or dry spells | Mildly toxic to pets |
| Therese Bugnet Rose | Direct sun (at least 4-6 hours) | Weekly while establishing; drought-tolerant thereafter | Pet-safe |
| Thessalian Aubrieta | Direct sun (at least 4-6 hours) | Low — water sparingly once established | Mildly toxic to pets |
| Thin-Leaved Sunflower | Medium indirect light (a couple of metres from a window) | Every 1–2 weeks; keep moderately moist | Pet-safe |
| Thistle Sage | Direct sun (at least 4-6 hours) | Very infrequent — once established, monthly or less in summer | Pet-safe |
| Thomas Edison Dahlia | Direct sun (at least 4-6 hours) | 2–3 times per week during growing season | Mildly toxic to pets |
| Thorn Apple | Direct sun (at least 4-6 hours) | Moderate, once or twice a week in dry spells | Toxic to pets |
| Thoroughwax | Direct sun (at least 4-6 hours) | Every 5–7 days; allow top inch to partially dry between waterings | Pet-safe |
| Threadleaf Coreopsis | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Pet-safe |
| Threadleaf Sawara Cypress | Direct sun (at least 4-6 hours) | Once per week to every 10 days when the top 2-3 cm of soil is dry; drought-tolerant once established | Toxic to pets |
| Threadleaf Tickseed 'Moonbeam' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days; infrequent once established | Pet-safe |
| Three-Coloured Bladderwort | Bright indirect light (just back from a sunny window) | Keep substrate consistently moist; water tray method year-round | Mildly toxic to pets |
| Three-Coloured Vanda | Direct sun (at least 4-6 hours) | Daily in warm growth; every 2-3 days when cool and dim | Pet-safe |
| Three-leaved Lantana | Direct sun (at least 4-6 hours) | Every 1–2 weeks | Toxic to pets |
| Three-Leaved Stork's Bill | Direct sun (at least 4-6 hours) | Water moderately in the growing season; keep nearly dry in winter | Mildly toxic to pets |
| Three-lobed Coneflower | Direct sun (at least 4-6 hours) | When the top 3–4 cm of soil is dry; roughly weekly in the growing season, more during drought | Mildly toxic to pets |
| Three-yoked Sage | Direct sun (at least 4-6 hours) | Low — every 10–14 days during active growth; minimal in winter | Mildly toxic to pets |
| Threeleaf Foamflower | Medium indirect light (a couple of metres from a window) | Approximately once or twice per week during the growing season; reduce in winter. | Mildly toxic to pets |
| Thrift | Direct sun (at least 4-6 hours) | Every 7–14 days, allowing soil to dry between waterings | Pet-safe |
| Throatwort | Direct sun (at least 4-6 hours) | Every 4–6 days; water when the top 2 cm of soil begins to dry | Pet-safe |
| Thunberg Spirea | Direct sun (at least 4-6 hours) | Weekly until established; occasional deep watering thereafter | Pet-safe |
| Thunberg's astilbe | Medium indirect light (a couple of metres from a window) | Regular — every 2–3 days in warm weather; reduce in cool, overcast periods | Pet-safe |
| Thyme-Leaved Edraianthus | Direct sun (at least 4-6 hours) | Low — allow soil to dry between waterings | Mildly toxic to pets |
| Thyme-leaved Fuchsia | Medium indirect light (a couple of metres from a window) | Regular — keep soil evenly moist | Pet-safe |
| Thyme-leaved Sandwort | Direct sun (at least 4-6 hours) | Low; water sparingly, allow soil to dry between waterings | Mildly toxic to pets |
| Tian Shan Everlasting | Direct sun (at least 4-6 hours) | Every 2–3 weeks; less in winter | Mildly toxic to pets |
| Tibetan whitebeam | Direct sun (at least 4-6 hours) | Weekly during establishment; low once mature | Mildly toxic to pets |
| Tidal Wave silver petunia | Direct sun (at least 4-6 hours) | Every 3–5 days in containers; every 7–10 days in garden beds | Pet-safe |
| Tiger Crow Orchid | Bright indirect light (just back from a sunny window) | When the bark mix is nearly dry, roughly every 5-7 days in growth | Pet-safe |
| Tiger Flower | Direct sun (at least 4-6 hours) | Regular watering during the growing season; reduce after flowering; dry storage in winter | Mildly toxic to pets |
| Tiger Lily | Direct sun (at least 4-6 hours) | When top 3 cm of soil is dry | Toxic to pets |
| Tiger Moth Orchid | Bright indirect light (just back from a sunny window) | When the bark is nearly dry, typically every 6-9 days | Pet-safe |
| Tiger Orchid | Bright indirect light (just back from a sunny window) | Abundant in growth (every 1-3 days); much drier in rest | Mildly toxic to pets |
| Tilia cordata | Direct sun (at least 4-6 hours) | Water young trees deeply every 7-14 days in dry spells for the first two seasons; established trees are largely self-sufficient | Pet-safe |
| Tilia tomentosa 'Petiolaris' | Direct sun (at least 4-6 hours) | Deep watering every 7-14 days during dry weather for the first two or three seasons; established trees seldom need it | Pet-safe |
| Tiny Sea Lavender | Direct sun (at least 4-6 hours) | Low — water sparingly, allowing soil to dry completely between sessions | Pet-safe |
| Tiramisu Heuchera | Bright indirect light (just back from a sunny window) | Keep soil evenly moist; water when the top 2-3 cm is dry, roughly every 5-7 days in summer | Pet-safe |
| Titanotrichum oldhamii | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 4-7 days in growth | Mildly toxic to pets |
| Toadshade Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist during spring and summer growing season; allow soil to dry slightly after summer dormancy. | Mildly toxic to pets |
| Toe toe | Direct sun (at least 4-6 hours) | Once or twice a week during establishment; monthly once established | Pet-safe |
| Toffee Twist Sedge | Direct sun (at least 4-6 hours) | Keep evenly moist; water once or twice weekly in heat, less when cool | Mildly toxic to pets |
| Tojen Toad Lily | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water when the surface begins to dry, roughly once or twice a week in summer | Mildly toxic to pets |
| Tokudama Flavocircinalis Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil begins to dry, about every 5-7 days during active growth | Toxic to pets |
| Tolumnia variegata | Bright indirect light (just back from a sunny window) | Daily to every other day when mounted; allow to dry fully between | Pet-safe |
| Tom Thumb Cactus | Direct sun (at least 4-6 hours) | When the top of the soil is dry, about every 7-10 days in summer; minimal in winter | Pet-safe |
| Tommies Crocus | Bright indirect light (just back from a sunny window) | No supplemental watering needed once established; relies on winter and spring rainfall | Mildly toxic to pets |
| Tompa Norway Spruce | Direct sun (at least 4-6 hours) | Every 7-10 days when establishing; deep watering as the top few cm of soil dry | Pet-safe |
| Toothed Fuchsia | Bright indirect light (just back from a sunny window) | Regular — keep evenly moist | Pet-safe |
| Toothed Nemesia | Direct sun (at least 4-6 hours) | Water regularly to keep compost evenly moist | Mildly toxic to pets |
| Toothpick plant | Direct sun (at least 4-6 hours) | Every 6–9 days; drought-tolerant when established | Mildly toxic to pets |
| Toothwort | Medium indirect light (a couple of metres from a window) | 2–3 times per week during the brief spring growth period; essentially none during summer dormancy | Pet-safe |
| Topeka Purple Coneflower | Direct sun (at least 4-6 hours) | Weekly during establishment; rainfall-dependent once mature (every 3–4 weeks in dry spells) | Pet-safe |
| Torch Mexican sunflower | Direct sun (at least 4-6 hours) | Weekly until established; every 10–14 days once mature; drought-tolerant | Mildly toxic to pets |
| Torenia fournieri | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, often every 2-4 days in summer | Mildly toxic to pets |
| Torenia fournieri 'Catalina Midnight Blue' | Bright indirect light (just back from a sunny window) | Keep consistently moist; water every 2-4 days, more in heat | Mildly toxic to pets |
| Torenia fournieri 'Summer Wave Large Violet' | Bright indirect light (just back from a sunny window) | Keep evenly moist; water every 2-4 days, daily for baskets in heat | Mildly toxic to pets |
| Tormentil | Bright indirect light (just back from a sunny window) | Moderate; keep soil lightly moist but not wet | Pet-safe |
| Totara | Direct sun (at least 4-6 hours) | When the topsoil dries, weekly while establishing then as needed | Toxic to pets |
| Touch of Class Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly during growth | Pet-safe |
| Trachelospermum asiaticum | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days while establishing | Pet-safe |
| Trachelospermum jasminoides 'Variegatum' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-10 days in growth | Pet-safe |
| Trachycarpus Latisectus | Bright indirect light (just back from a sunny window) | Regularly through the growing season; keep evenly moist but never soggy | Pet-safe |
| Trachycarpus Takil | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in summer; reduce sharply over winter | Pet-safe |
| Trailing Abutilon | Bright indirect light (just back from a sunny window) | Freely in growth (spring–autumn); sparingly in winter | Mildly toxic to pets |
| Trailing African daisy | Direct sun (at least 4-6 hours) | Once or twice a week during active growth; reduce to once a week or less once established | Pet-safe |
| Trailing African Violet 'Rob's Vanilla Trail' | Bright indirect light (just back from a sunny window) | When the soil surface is just dry, about every 5-7 days | Pet-safe |
| Trailing Azalea | Direct sun (at least 4-6 hours) | Moderate; water during dry spells in the growing season but ensure rapid drainage. | Toxic to pets |
| Trailing Cape Primrose | Bright indirect light (just back from a sunny window) | every 7–10 days in active growth, every 14–21 days in winter | Pet-safe |
| Trailing Fuchsia | Bright indirect light (just back from a sunny window) | Every 7-10 days in summer; very sparingly in winter | Pet-safe |
| Trailing globe amaranth | Direct sun (at least 4-6 hours) | Every 5–7 days; quite drought-tolerant | Pet-safe |
| Trailing Ice Plant | Direct sun (at least 4-6 hours) | Every 2–3 weeks (allow soil to dry completely between waterings) | Pet-safe |
| Trailing Iceplant | Direct sun (at least 4-6 hours) | Every 2–3 weeks during the growing season; minimal in winter | Mildly toxic to pets |
| Trailing Lantana | Direct sun (at least 4-6 hours) | Every 1–2 weeks (drought-tolerant when established) | Toxic to pets |
| Trailing Rock Jasmine | Bright indirect light (just back from a sunny window) | Moderate; allow top 2 cm to dry between waterings | Mildly toxic to pets |
| Transparent Moor Grass | Direct sun (at least 4-6 hours) | Every 7-14 days; keep moderately moist | Pet-safe |
| Transparent Tall Moor Grass | Bright indirect light (just back from a sunny window) | Weekly during establishment; less once settled | Pet-safe |
| Transylvanian Hepatica | Medium indirect light (a couple of metres from a window) | Every 5–7 days in spring and autumn; every 10–14 days in summer | Mildly toxic to pets |
| Transylvanian Pink | Direct sun (at least 4-6 hours) | Infrequent; allow soil to dry well between waterings | Mildly toxic to pets |
| Transylvanian Sage | Bright indirect light (just back from a sunny window) | Moderate — every 7–10 days in summer | Mildly toxic to pets |
| Treasure flower | Direct sun (at least 4-6 hours) | Every 10–14 days once established; weekly when young | Mildly toxic to pets |
| Tree Dahlia | Direct sun (at least 4-6 hours) | 2-3 times per week during active growth in summer; deeply, to encourage a strong root system | Mildly toxic to pets |
| Tree Fuchsia | Bright indirect light (just back from a sunny window) | Every 5-7 days in summer, reducing to every 14 days in winter | Pet-safe |
| Tree heath | Direct sun (at least 4-6 hours) | Fortnightly during the first growing season; drought-tolerant once established | Pet-safe |
| Tree Peony | Direct sun (at least 4-6 hours) | Deeply every 7-10 days in the first two years and during dry spells; established shrubs are drought-tolerant | Toxic to pets |
| Tree rhododendron | Bright indirect light (just back from a sunny window) | Every 7–10 days in the growing season; monthly in winter | Toxic to pets |
| Trevi Fountain Pulmonaria | Low light (north window or shaded room) | Keep soil evenly moist; water every 4-6 days in dry weather, more in containers | Mildly toxic to pets |
| Trewithen Blue Ceanothus | Direct sun (at least 4-6 hours) | Every 7-10 days during establishment; established plants are drought-tolerant and need supplemental watering only in prolonged dry periods in summer | Mildly toxic to pets |
| Trident Maple | Direct sun (at least 4-6 hours) | Water when the top of the soil begins to dry; bonsai often need daily water in summer | Mildly toxic to pets |
| Trident Maple 'Kifu' | Direct sun (at least 4-6 hours) | When the surface begins to dry, frequently once or twice daily in summer heat | Mildly toxic to pets |
| Tropaeolum majus 'Jewel of Africa' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, roughly every 4-7 days; containers more often in heat | Pet-safe |
| Tropical Sage | Medium indirect light (a couple of metres from a window) | Regular while establishing; reduced once established | Pet-safe |
| True lily | Bright indirect light (just back from a sunny window) | Keep evenly moist while growing, every 5-7 days | Toxic to pets |
| Trumpet Gentian | Direct sun (at least 4-6 hours) | Regular during the growing season; reduced but not eliminated in winter | Mildly toxic to pets |
| Trumpeter Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly | Pet-safe |
| Tube Beardtongue | Direct sun (at least 4-6 hours) | Low to moderate; drought-tolerant once established | Mildly toxic to pets |
| Tuberous Begonia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of compost is dry, roughly every 3-5 days in summer | Toxic to pets |
| Tuberous Begonia 'Nonstop' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 4-7 days in growth | Toxic to pets |
| Tuberous Catmint | Direct sun (at least 4-6 hours) | Every 10–14 days in summer; minimal watering in winter dormancy | Pet-safe |
| Tuberous Cranesbill | Direct sun (at least 4-6 hours) | Sparingly in summer; moderate in spring growing season | Mildly toxic to pets |
| Tufted Hair Grass | Bright indirect light (just back from a sunny window) | Keep soil consistently moist, watering deeply 1-2 times weekly in dry spells | Mildly toxic to pets |
| Tufted Loosestrife | Medium indirect light (a couple of metres from a window) | Permanently wet to shallow aquatic; bog garden or shallow pond margin | Pet-safe |
| Tufted Vetch | Direct sun (at least 4-6 hours) | Low to moderate — tolerates periodic dry spells once established | Mildly toxic to pets |
| Tulip | Direct sun (at least 4-6 hours) | Water at planting; rely on rainfall after | Toxic to pets |
| Tulip Anthurium | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is dry, roughly every 5-7 days in growth | Toxic to pets |
| Tulipa 'Angelique' | Direct sun (at least 4-6 hours) | Moist during autumn rooting and spring growth; dry off as foliage yellows | Toxic to pets |
| Tulipa 'Apeldoorn' | Direct sun (at least 4-6 hours) | Keep soil moist in growth; dry while dormant | Toxic to pets |
| Tulipa 'Ballerina' | Direct sun (at least 4-6 hours) | Moist through autumn rooting and spring growth; dry off as foliage yellows | Toxic to pets |
| Tulipa 'Black Parrot' | Direct sun (at least 4-6 hours) | Moist during autumn rooting and spring growth; withhold as foliage dies back | Toxic to pets |
| Tulipa 'Estella Rijnveld' | Direct sun (at least 4-6 hours) | Keep soil evenly moist during autumn rooting and spring growth; let it dry between waterings once foliage yellows | Toxic to pets |
| Tulipa 'Flaming Parrot' | Direct sun (at least 4-6 hours) | Moist during autumn rooting and spring growth; dry off as foliage yellows | Toxic to pets |
| Tulipa 'Ice Cream' | Direct sun (at least 4-6 hours) | Moist during autumn rooting and spring growth; dry off as foliage yellows | Toxic to pets |
| Tulipa 'Menton' | Direct sun (at least 4-6 hours) | Water in at planting, then only during dry spells in spring | Toxic to pets |
| Tulipa 'Monsella' | Direct sun (at least 4-6 hours) | Moist in active spring growth; dry through summer dormancy | Toxic to pets |
| Tulipa 'Prinses Irene' | Direct sun (at least 4-6 hours) | Keep soil moist while growing in spring; let bulbs stay dry in summer dormancy | Toxic to pets |
| Tulipa 'Purissima' | Direct sun (at least 4-6 hours) | Moist during autumn rooting and spring growth; dry off as foliage yellows | Toxic to pets |
| Tulipa 'Queen of Night' | Direct sun (at least 4-6 hours) | Keep soil moist in growth; dry while dormant | Toxic to pets |
| Tulipa 'Rococo' | Direct sun (at least 4-6 hours) | Moist during autumn rooting and spring growth; dry off as foliage yellows | Toxic to pets |
| Tulipa 'Tulipa clusiana' | Direct sun (at least 4-6 hours) | Rainfall in spring; keep dry during summer dormancy | Toxic to pets |
| Tulipa sylvestris | Direct sun (at least 4-6 hours) | Rainfall in most settings; tolerates moister ground than hybrids | Toxic to pets |
| Tunic Flower | Direct sun (at least 4-6 hours) | Low; water sparingly and only when the top 2–3 cm of soil is fully dry | Mildly toxic to pets |
| Tuolumne Fawn Lily | Medium indirect light (a couple of metres from a window) | Consistently moist during growth (late winter to early summer); do not allow to dry out even during dormancy | Mildly toxic to pets |
| Turk's Cap Lily | Bright indirect light (just back from a sunny window) | Regular during active growth in spring and summer; keep soil consistently moist but not waterlogged | Toxic to pets |
| Turkestan Tulip | Direct sun (at least 4-6 hours) | Minimal; water once at planting; rely on natural rainfall during growth; completely dry during summer dormancy | Toxic to pets |
| Turkey Oak | Direct sun (at least 4-6 hours) | Occasional once established; more frequent in first 2–3 years | Mildly toxic to pets |
| Turkish Catmint | Direct sun (at least 4-6 hours) | Every 10–14 days in summer; very sparingly in winter | Pet-safe |
| Turkish Fir | Direct sun (at least 4-6 hours) | When the top 5-8 cm of soil is dry for young trees, roughly every 10-14 days in the first 2-3 years | Mildly toxic to pets |
| Turkish Pink Sage | Direct sun (at least 4-6 hours) | Every 10–14 days in summer; minimal in winter | Mildly toxic to pets |
| Turkish Red Sage | Bright indirect light (just back from a sunny window) | Allow to dry between waterings | Pet-safe |
| Turkish White Sage | Direct sun (at least 4-6 hours) | Every 10-14 days; minimal once dormant in summer heat | Pet-safe |
| Turquoise Puya | Direct sun (at least 4-6 hours) | weekly in summer, monthly in winter | Pet-safe |
| Tussock Needlegrass | Direct sun (at least 4-6 hours) | Every 2-3 weeks during the first growing season; essentially rain-fed once established | Mildly toxic to pets |
| Tweedy's Lewisia | Bright indirect light (just back from a sunny window) | Regular in spring; near-dry from midsummer to early autumn | Pet-safe |
| Twinkle Oncidium | Bright indirect light (just back from a sunny window) | When the top of the mix begins to dry, about every 4-6 days | Pet-safe |
| Twinleaf | Medium indirect light (a couple of metres from a window) | 2 times per week during spring growth; reduce through summer | Mildly toxic to pets |
| Twinspur | Direct sun (at least 4-6 hours) | 2–3 times per week during active growth; reduce during cooler periods | Pet-safe |
| Twisted Trillium | Medium indirect light (a couple of metres from a window) | Moderate moisture in spring; reduced in summer dormancy | Mildly toxic to pets |
| Two-Colour Vygie | Direct sun (at least 4-6 hours) | Every 2–3 weeks in the growing season; monthly or less in winter | Mildly toxic to pets |
| Two-Flowered Everlasting Pea | Direct sun (at least 4-6 hours) | Every 7–10 days during dry spells; rarely needs watering once established | Mildly toxic to pets |
| Two-leaf Squill | Bright indirect light (just back from a sunny window) | Naturally watered in spring; needs no supplemental irrigation once established | Toxic to pets |
| Two-Row Stonecrop | Direct sun (at least 4-6 hours) | Every 10-14 days until established; essentially rain-fed once rooted | Pet-safe |
| Two-toned Pineapple Lily | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 7-10 days during the growing season | Toxic to pets |
| Typha angustifolia | Direct sun (at least 4-6 hours) | Keep permanently wet; grow in standing water up to about 30-50 cm deep or saturated soil | Mildly toxic to pets |
| Typha latifolia | Direct sun (at least 4-6 hours) | Keep permanently wet; grow in standing water 0-30 cm deep or in saturated soil | Mildly toxic to pets |
| Typha minima | Direct sun (at least 4-6 hours) | Keep permanently wet; grow in shallow water up to about 5-15 cm over the crown or in saturated soil | Mildly toxic to pets |
| Umbel Sun Rose | Direct sun (at least 4-6 hours) | Very low — minimal irrigation needed; drought-tolerant once established | Mildly toxic to pets |
| Umbrella Magnolia | Medium indirect light (a couple of metres from a window) | Weekly during dry spells; keep soil evenly moist but not waterlogged | Pet-safe |
| Unbranched Bur-reed | Direct sun (at least 4-6 hours) | Permanently aquatic or waterlogged; tolerates 0–60 cm (0–24 in) water depth | Pet-safe |
| Upright European Hornbeam | Direct sun (at least 4-6 hours) | Moderate; water regularly for first 2–3 seasons; rainfall-dependent once established | Pet-safe |
| Upright Hedge Parsley | Medium indirect light (a couple of metres from a window) | Moderate; keep soil evenly moist | Mildly toxic to pets |
| Upright Plum Yew | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Upright Prairie Coneflower | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; very drought-tolerant | Pet-safe |
| Uproar Rose zinnia | Direct sun (at least 4-6 hours) | Regular; deep watering 2–3 times per week at soil level | Pet-safe |
| Urmia Tulip | Direct sun (at least 4-6 hours) | Moderate in spring; dry in summer | Toxic to pets |
| Urn Plant (Aechmea fasciata) | Bright indirect light (just back from a sunny window) | Keep ~1 inch of water in the central cup at all times; flush and refill monthly. Lightly moisten the potting mix when the top inch dries; reduce in winter. | Mildly toxic to pets |
| Utricularia sandersonii | Bright indirect light (just back from a sunny window) | Keep the media constantly wet, standing in 1-2 cm of water | Mildly toxic to pets |
| Utricularia subulata | Direct sun (at least 4-6 hours) | Keep constantly wet to waterlogged; stand in 1-2 cm of water at all times | Mildly toxic to pets |
| Valais fescue | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; more frequent only during establishment | Pet-safe |
| Valentine Bleeding Heart | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water every 4-6 days in spring, easing off as it goes dormant | Toxic to pets |
| Valentine's Crown Vetch | Direct sun (at least 4-6 hours) | Low to moderate — once every 2–3 weeks when established | Toxic to pets |
| Vallisneria-Leaved Butterwort | Bright indirect light (just back from a sunny window) | Keep constantly moist to wet during the growing season (spring–autumn); reduce to near-dry during winter hibernaculum phase | Mildly toxic to pets |
| Vanda 'Miss Joaquim' | Direct sun (at least 4-6 hours) | Daily in warm, bright conditions; every 2-3 days if cooler | Pet-safe |
| Vanda Orchid | Direct sun (at least 4-6 hours) | Daily in warm months; 2-3x weekly in winter | Mildly toxic to pets |
| Vandell's Rock Jasmine | Direct sun (at least 4-6 hours) | Very low — water from below, keep dry in winter | Mildly toxic to pets |
| Varied-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Every 2–3 weeks when established; more frequently in the first season | Mildly toxic to pets |
| Variegata Brunnera | Low light (north window or shaded room) | Keep soil reliably moist; water when the top 2-3 cm dries, roughly every 4-6 days in warm spells | Mildly toxic to pets |
| Variegata Purple Moor Grass | Bright indirect light (just back from a sunny window) | Every 7-14 days; keep moderately moist to moist | Pet-safe |
| Variegated Cord Grass | Direct sun (at least 4-6 hours) | Keep consistently moist to wet; never let it dry out | Mildly toxic to pets |
| Variegated Greater Periwinkle | Bright indirect light (just back from a sunny window) | Every 5–7 days during active growth; reduce to every 10–14 days in cooler months | Toxic to pets |
| Variegated Greater Pond Sedge | Bright indirect light (just back from a sunny window) | Keep consistently wet — tolerates standing water | Pet-safe |
| Variegated Hiba Arborvitae | Bright indirect light (just back from a sunny window) | Once every 7-10 days, keeping soil consistently moist but not waterlogged | Toxic to pets |
| Variegated Incense Cedar | Direct sun (at least 4-6 hours) | Once every 10-14 days once established; more frequently in its first two seasons | Mildly toxic to pets |
| Variegated Japanese Spurge | Medium indirect light (a couple of metres from a window) | Every 5–7 days during establishment; once established, water during dry spells | Mildly toxic to pets |
| Variegated Lilyturf | Medium indirect light (a couple of metres from a window) | Weekly during establishment; established plants are drought-tolerant, needing water only during prolonged summer drought | Mildly toxic to pets |
| Variegated pieris | Bright indirect light (just back from a sunny window) | Weekly; do not allow soil to dry out | Toxic to pets |
| Variegated Purple Moor Grass | Bright indirect light (just back from a sunny window) | Regular; keep soil consistently moist | Pet-safe |
| Variegated Purple Moor Grass | Bright indirect light (just back from a sunny window) | Weekly during growing season; keep consistently moist | Pet-safe |
| variegated silver grass | Direct sun (at least 4-6 hours) | Weekly during the growing season; reduce in autumn and winter | Pet-safe |
| Variegated Solomon's Seal | Low light (north window or shaded room) | Every 5-7 days in active growth; drought-tolerant once established | Toxic to pets |
| Variegated Velvet Grass | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Pet-safe |
| Variegated Yellow Sedge | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water every 5-7 days in dry spells and never let containers dry out | Mildly toxic to pets |
| Vasey's Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist through spring; reduce over summer dormancy | Mildly toxic to pets |
| Veilchenblau Rose | Bright indirect light (just back from a sunny window) | Deeply once or twice weekly while establishing; mature plants when the top few centimetres of soil dry, and they tolerate some drought | Pet-safe |
| Veitch Fir | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once mature | Pet-safe |
| Velvet Ash | Direct sun (at least 4-6 hours) | Low once established; deep watering every 2–4 weeks in summer heat | Pet-safe |
| Velvet Queen sunflower | Direct sun (at least 4-6 hours) | Weekly, more often in hot dry spells | Pet-safe |
| Velvet Sage | Bright indirect light (just back from a sunny window) | Weekly | Pet-safe |
| Verbena × hybrida 'Obsession Coral Eye' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 3-5 days in summer | Mildly toxic to pets |
| Verbena × hybrida 'Superbena Stormburst' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 2-4 days in summer | Mildly toxic to pets |
| Veronica beccabunga | Direct sun (at least 4-6 hours) | Keep permanently wet; never let the rootzone dry out | Mildly toxic to pets |
| Veronica longifolia 'Blauriesin' | Direct sun (at least 4-6 hours) | When the top few centimetres of soil are drying, about weekly in summer | Mildly toxic to pets |
| Veronica spicata 'Royal Candles' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly weekly in the first season | Mildly toxic to pets |
| Veronica spicata subsp. incana | Direct sun (at least 4-6 hours) | Every 10-14 days once established, when soil is dry | Mildly toxic to pets |
| Veronicastrum virginicum | Direct sun (at least 4-6 hours) | Keep soil consistently moist; water deeply in dry spells | Mildly toxic to pets |
| Veronicastrum virginicum 'Fascination' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, roughly every 5-7 days | Mildly toxic to pets |
| Veterans' Honor Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly during growth | Pet-safe |
| Vilmorin Japanese Cedar | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Vilmorin's rowan | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once mature | Mildly toxic to pets |
| Viola 'Sorbet Raspberry' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, about every 3-5 days; containers more often | Pet-safe |
| Viola × wittrockiana 'Delta Pure Yellow' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, typically every 3-5 days; containers dry faster | Pet-safe |
| Viola cornuta 'Etain' | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, generally every 3-5 days; more in containers and heat | Pet-safe |
| Violet petunia | Direct sun (at least 4-6 hours) | Every 7–10 days in borders; containers may need more frequent watering | Pet-safe |
| Violet Sage | Direct sun (at least 4-6 hours) | Every 10–14 days once established | Pet-safe |
| Violet Wood Sorrel | Bright indirect light (just back from a sunny window) | Moderate during active growth (spring); very little during summer dormancy | Toxic to pets |
| Violet-Flowered Sage | Direct sun (at least 4-6 hours) | Every 7 days in summer; every 14–21 days in winter | Mildly toxic to pets |
| Viper's Bugloss | Direct sun (at least 4-6 hours) | Infrequent once established; drought-tolerant | Mildly toxic to pets |
| Virgin's Bower | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 10-14 days once established | Toxic to pets |
| Virginia Bluebells | Medium indirect light (a couple of metres from a window) | 1–2 inches per week in spring; minimal needed once dormant | Pet-safe |
| Virginia Pine Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm is dry, frequently daily in summer and every few days in cooler months | Pet-safe |
| Virginia Spring Beauty | Bright indirect light (just back from a sunny window) | Moderate in spring; negligible once dormant in summer | Pet-safe |
| Virginia Stock | Bright indirect light (just back from a sunny window) | Weekly (keep soil evenly moist but not waterlogged) | Mildly toxic to pets |
| Vitis coignetiae | Direct sun (at least 4-6 hours) | Water young vines in dry spells; established plants are largely self-sufficient | Toxic to pets |
| Vivellii winter heath | Direct sun (at least 4-6 hours) | Weekly for new plantings; every 2–3 weeks for established plants during dry periods | Pet-safe |
| Voodoo Lily | Bright indirect light (just back from a sunny window) | Water the leaf stage when the top 2-3 cm of soil is dry, roughly every 5-7 days; keep the dormant tuber dry | Toxic to pets |
| Wagner's Sage | Bright indirect light (just back from a sunny window) | Water regularly to maintain consistent moisture | Pet-safe |
| Waldbrunn Spruce | Direct sun (at least 4-6 hours) | Every 7-10 days while establishing; deep watering when the top 5 cm of soil dries | Pet-safe |
| Waldensian Saxifrage | Direct sun (at least 4-6 hours) | Very low — allow soil to dry between waterings; withhold almost entirely in winter | Pet-safe |
| Walker's Low Catmint | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry; roughly every 7-10 days while establishing, then rarely | Mildly toxic to pets |
| Walker's Low Catmint | Direct sun (at least 4-6 hours) | Every 7–14 days once established | Pet-safe |
| Wall Rue | Bright indirect light (just back from a sunny window) | Rarely needs watering in the ground; water container plants only when the crevice substrate dries | Pet-safe |
| Wallich's Cranesbill | Bright indirect light (just back from a sunny window) | Once or twice weekly during dry spells once established | Pet-safe |
| Warming's Sinningia | Bright indirect light (just back from a sunny window) | Moderate during active growth; dry during dormancy | Pet-safe |
| Water Avens | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist to wet; never let it dry out | Mildly toxic to pets |
| Water Forget-me-not | Bright indirect light (just back from a sunny window) | Permanently moist to marginal aquatic; up to 10 cm over crown | Mildly toxic to pets |
| Water Horsetail | Direct sun (at least 4-6 hours) | Submerged or saturated | Mildly toxic to pets |
| Water Lily Cactus | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days in spring and summer; every 3-4 weeks in autumn; almost none in winter | Pet-safe |
| Water Speedwell | Direct sun (at least 4-6 hours) | Permanently wet to shallow submersion | Pet-safe |
| Water Tupelo | Direct sun (at least 4-6 hours) | Constant to seasonally flooded; extremely wet tolerant | Mildly toxic to pets |
| Water Violet | Bright indirect light (just back from a sunny window) | Fully submerged aquatic; grows in 20–80 cm of water | Pet-safe |
| Waterfall Gladiolus | Direct sun (at least 4-6 hours) | Every 5-7 days during active growth; reduce significantly as foliage dies back | Mildly toxic to pets |
| Waterlily Tulip | Direct sun (at least 4-6 hours) | Rainfall-dependent during growing season; needs dry summer dormancy | Toxic to pets |
| Wave Petunia | Direct sun (at least 4-6 hours) | When the top 2-3 cm of soil is dry, often daily in baskets and hot weather | Pet-safe |
| Wave purple petunia | Direct sun (at least 4-6 hours) | Every 3–5 days in containers; every 7–10 days in borders | Pet-safe |
| wavy hair grass | Bright indirect light (just back from a sunny window) | Water every 1-2 weeks; drought-tolerant once established in cool climates | Mildly toxic to pets |
| Wavy Nerine | Direct sun (at least 4-6 hours) | Very little to none in summer dormancy; regular from when flower spikes emerge in autumn through spring; stop as foliage dies back | Toxic to pets |
| Wavyleaf Coneflower | Direct sun (at least 4-6 hours) | Weekly during establishment (first season); monthly or rainfall-dependent once mature | Pet-safe |
| Wax Begonia | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, about every 5-7 days | Toxic to pets |
| Wax-Leaf Begonia | Bright indirect light (just back from a sunny window) | When the top 1–2 cm of soil feels dry | Toxic to pets |
| wayfaring tree | Direct sun (at least 4-6 hours) | Weekly when young; rarely needed once established | Mildly toxic to pets |
| Webb's Germander | Direct sun (at least 4-6 hours) | Sparingly; allow soil to dry between waterings | Mildly toxic to pets |
| Weeping Blue Atlas Cedar | Direct sun (at least 4-6 hours) | Every 1-2 weeks while young, then only in drought | Mildly toxic to pets |
| Weeping Blue Atlas Cedar | Direct sun (at least 4-6 hours) | Weekly during establishment (2–3 years); then rainfall-dependent | Mildly toxic to pets |
| Weeping Brown Sedge | Bright indirect light (just back from a sunny window) | Weekly or when the top 3 cm of soil is dry | Pet-safe |
| Weeping Eastern Hemlock | Medium indirect light (a couple of metres from a window) | Every 1–2 weeks; more in hot or dry conditions | Pet-safe |
| Weeping Eastern Hemlock | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days | Mildly toxic to pets |
| Weeping European Larch | Direct sun (at least 4-6 hours) | Weekly during establishment; less once established | Pet-safe |
| Weeping European Larch | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days during the growing season | Mildly toxic to pets |
| weeping forsythia | Direct sun (at least 4-6 hours) | Weekly during first growing season; established plants need watering only during prolonged drought | Mildly toxic to pets |
| Weeping Giant Sequoia | Direct sun (at least 4-6 hours) | Every 1–2 weeks when young; monthly once established in moist climates | Pet-safe |
| Weeping Japanese Larch | Direct sun (at least 4-6 hours) | Once every 7-10 days during the growing season; reduce in winter when dormant | Mildly toxic to pets |
| Weeping Love Grass | Direct sun (at least 4-6 hours) | Every 3–4 weeks once established; weekly during establishment | Pet-safe |
| Weeping Nootka Cypress | Direct sun (at least 4-6 hours) | Regularly during establishment; moderate once mature | Pet-safe |
| Weeping Nootka Cypress | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days for young plants | Mildly toxic to pets |
| Weeping Norway Spruce | Direct sun (at least 4-6 hours) | Keep soil evenly moist; water weekly in dry spells, more for young trees | Mildly toxic to pets |
| Weeping silver pear | Direct sun (at least 4-6 hours) | Weekly when establishing; monthly once established | Mildly toxic to pets |
| Weeping White Mulberry | Direct sun (at least 4-6 hours) | Weekly for first two years; monthly once established in temperate climates | Mildly toxic to pets |
| Weigela 'Bristol Ruby' | Direct sun (at least 4-6 hours) | Weekly while establishing; established shrubs need water mainly in dry spells | Mildly toxic to pets |
| Weigela 'Eva Rathke' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil feels dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Weigela 'Florida Purpurea' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Weigela 'Midnight Wine' | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Weigela 'My Monet' | Direct sun (at least 4-6 hours) | Water when the top 5 cm of soil dries, about weekly while establishing | Pet-safe |
| Weigela 'My Monet' | Bright indirect light (just back from a sunny window) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in the growing season | Mildly toxic to pets |
| Weigela 'Nana Variegata' | Bright indirect light (just back from a sunny window) | When the top 3-4 cm of soil is dry, roughly every 7-10 days once established | Pet-safe |
| Weigela 'Red Prince' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during active growth | Mildly toxic to pets |
| Weigela 'Sunny Princess' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Weigela 'Wine & Roses' | Direct sun (at least 4-6 hours) | Water when the top 5 cm of soil is dry, about weekly while establishing | Pet-safe |
| Weigela 'Wine & Roses' | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-10 days during the growing season | Mildly toxic to pets |
| Welsh Poppy | Medium indirect light (a couple of metres from a window) | Moderate; moist but not waterlogged | Toxic to pets |
| Welwitsch's Thrift | Direct sun (at least 4-6 hours) | Every 2–3 weeks; minimal in winter | Mildly toxic to pets |
| West Texas Sage | Direct sun (at least 4-6 hours) | Low; drought-tolerant once established | Pet-safe |
| Western Arborvitae Zebrina | Direct sun (at least 4-6 hours) | Deeply every 5-7 days the first two years, then during dry spells | Mildly toxic to pets |
| Western Bog Laurel | Direct sun (at least 4-6 hours) | Frequent to constant; keep wet | Toxic to pets |
| Western Columbine | Bright indirect light (just back from a sunny window) | Every 5–7 days during active growth; reduce after flowering | Toxic to pets |
| Western Hemlock | Medium indirect light (a couple of metres from a window) | Weekly during establishment; regular moisture long-term | Pet-safe |
| Western Ironweed | Direct sun (at least 4-6 hours) | Low to moderate — drought-tolerant once established | Mildly toxic to pets |
| Western Larch | Direct sun (at least 4-6 hours) | Weekly during establishment; thereafter relies on natural precipitation | Pet-safe |
| Western Red Cedar | Direct sun (at least 4-6 hours) | Regular — water deeply once or twice a week until established; drought-sensitive | Pet-safe |
| Western Skunk Cabbage | Medium indirect light (a couple of metres from a window) | Permanently moist to wet; boggy or waterlogged conditions required | Toxic to pets |
| Western Spirea | Direct sun (at least 4-6 hours) | Every 5-7 days or as needed to keep soil consistently moist | Pet-safe |
| Western Sunflower | Direct sun (at least 4-6 hours) | Every 2–4 weeks once established; extremely drought-tolerant | Pet-safe |
| Western White Trillium | Medium indirect light (a couple of metres from a window) | Consistently moist spring through early summer; reduced but not completely dry in summer dormancy. | Mildly toxic to pets |
| Wheat cockscomb | Direct sun (at least 4-6 hours) | Every 5–7 days in active growth; reduce in cooler periods | Pet-safe |
| Wherry's Foamflower | Medium indirect light (a couple of metres from a window) | Keep soil evenly moist; water about weekly, more in dry spells | Mildly toxic to pets |
| Wherry's Foamflower | Medium indirect light (a couple of metres from a window) | Once or twice per week in the growing season; reduce significantly in winter. | Mildly toxic to pets |
| Whirling Butterflies Gaura | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 7-14 days during the growing season | Pet-safe |
| Whirlwind Blue Fan Flower | Direct sun (at least 4-6 hours) | When the top 2-3 cm of potting mix is dry, roughly every 4-6 days in summer | Pet-safe |
| White Anthurium | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 7-10 days | Toxic to pets |
| White Arrow Arum | Bright indirect light (just back from a sunny window) | Continuously moist to waterlogged; never allow to dry out | Toxic to pets |
| White Ash | Direct sun (at least 4-6 hours) | Moderate; water weekly when young; moderate drought tolerance once established | Mildly toxic to pets |
| White Baneberry | Medium indirect light (a couple of metres from a window) | 2–3 times per week in growing season; weekly when dormant | Toxic to pets |
| White Beardtongue | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; minimal in winter | Pet-safe |
| White Bleeding Heart | Medium indirect light (a couple of metres from a window) | Every 3-5 days in active growth; reduce once dormant | Toxic to pets |
| White Brodiaea | Direct sun (at least 4-6 hours) | Regular during active growth; dry during summer dormancy | Mildly toxic to pets |
| White Campion | Bright indirect light (just back from a sunny window) | Low to moderate; allow soil to approach dryness between waterings | Mildly toxic to pets |
| White Comfrey | Medium indirect light (a couple of metres from a window) | Every 5–10 days during dry periods | Mildly toxic to pets |
| white double camellia | Bright indirect light (just back from a sunny window) | Regularly throughout the year; moisture critical in summer and autumn | Mildly toxic to pets |
| White Enkianthus | Bright indirect light (just back from a sunny window) | Regularly; soil should stay evenly moist | Mildly toxic to pets |
| White Fir | Direct sun (at least 4-6 hours) | Every 1–2 weeks during establishment; largely drought-tolerant once mature | Pet-safe |
| White Freesia | Direct sun (at least 4-6 hours) | Moderate during active growth (autumn to spring); completely dry during summer dormancy | Pet-safe |
| White Ginger Lily | Bright indirect light (just back from a sunny window) | Water generously every 2–4 days in active growth; reduce to sparingly in winter dormancy | Mildly toxic to pets |
| White Grand Lotus | Direct sun (at least 4-6 hours) | Aquatic — permanently in still or slow-moving water | Mildly toxic to pets |
| White laceflower | Direct sun (at least 4-6 hours) | Every 5–7 days; allow the top 2 cm of soil to dry between waterings | Pet-safe |
| White Magic Grape Hyacinth | Direct sun (at least 4-6 hours) | Moderate in spring; dry from early summer through autumn | Mildly toxic to pets |
| White Marsh Marigold | Bright indirect light (just back from a sunny window) | Permanently moist to boggy; crown should sit just above water level | Mildly toxic to pets |
| White Marsh Marigold | Bright indirect light (just back from a sunny window) | Permanently moist to wet; boggy soil or shallow pondside | Mildly toxic to pets |
| White mountain heather | Direct sun (at least 4-6 hours) | Consistently moist during the growing season; reduce in winter | Pet-safe |
| White Mugwort | Medium indirect light (a couple of metres from a window) | Weekly or when top 2–3 cm of soil dries | Mildly toxic to pets |
| White Nancy Dead Nettle | Medium indirect light (a couple of metres from a window) | Every 7–10 days during active growth; reduce in winter | Pet-safe |
| White Passionflower | Direct sun (at least 4-6 hours) | Once a week during dry spells; less in winter | Pet-safe |
| White Perfection Darley Dale heath | Direct sun (at least 4-6 hours) | Weekly during establishment; every 2–3 weeks once established | Pet-safe |
| White Periwinkle | Medium indirect light (a couple of metres from a window) | Weekly during establishment; self-sufficient in average rainfall once established | Toxic to pets |
| White Prairie Clover | Direct sun (at least 4-6 hours) | Water to establish; afterwards highly drought-tolerant, seldom needs watering | Mildly toxic to pets |
| White Rain Lily | Direct sun (at least 4-6 hours) | Regular moisture with periodic dry spells | Mildly toxic to pets |
| White Rain Lily | Direct sun (at least 4-6 hours) | Moderately during growth; a dry period followed by watering triggers blooming | Toxic to pets |
| White Skunk Cabbage | Medium indirect light (a couple of metres from a window) | Continuously moist to waterlogged; never allow to dry out | Toxic to pets |
| White Spruce | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; regular watering for first 2 years | Mildly toxic to pets |
| White St Dabeoc's Heath | Bright indirect light (just back from a sunny window) | Moderate — water when top 2–3 cm of soil is dry | Mildly toxic to pets |
| White Stonecrop | Direct sun (at least 4-6 hours) | When soil is dry, roughly every 10-14 days in summer; little to none in winter | Pet-safe |
| White Towers Toad Lily | Medium indirect light (a couple of metres from a window) | Keep evenly moist; water when the surface starts to dry, often once or twice weekly in summer | Mildly toxic to pets |
| White Trillium | Medium indirect light (a couple of metres from a window) | Weekly during spring growth; reduce after dormancy | Mildly toxic to pets |
| White Trout Lily | Medium indirect light (a couple of metres from a window) | Keep consistently moist while in growth (spring); reduce after dormancy | Mildly toxic to pets |
| White Trumpet Pitcher | Direct sun (at least 4-6 hours) | Keep constantly wet via the tray method, standing in 1-3 cm of water through the growing season | Pet-safe |
| White Water Lily | Direct sun (at least 4-6 hours) | Permanent aquatic — always submerged in 45-90 cm of water | Mildly toxic to pets |
| White Wild Indigo | Direct sun (at least 4-6 hours) | Water the first season; established plants need little to no watering | Mildly toxic to pets |
| White Wild Quinine | Direct sun (at least 4-6 hours) | Water to establish, then sparingly; drought-tolerant once rooted | Mildly toxic to pets |
| White wood aster | Medium indirect light (a couple of metres from a window) | Every 1–2 weeks during establishment; largely self-sufficient once established in woodland settings | Pet-safe |
| White Wood Aster | Medium indirect light (a couple of metres from a window) | When the top 3-5 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| White Young's Barrenwort | Medium indirect light (a couple of metres from a window) | Water weekly, or when the top 2 cm of soil dries, particularly during establishment; reduce frequency once settled | Mildly toxic to pets |
| White-Bark Magnolia | Bright indirect light (just back from a sunny window) | Weekly during dry spells for the first 3 years; every 2 weeks when established | Pet-safe |
| White-blue Sage | Direct sun (at least 4-6 hours) | Low to moderate — seasonal wet–dry cycle; allow soil to dry between waterings | Mildly toxic to pets |
| White-flowered Beardtongue | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; minimal in winter | Mildly toxic to pets |
| White-Leaved Rock Rose | Direct sun (at least 4-6 hours) | Occasional — every 2–3 weeks when established; weekly in the first season | Mildly toxic to pets |
| White-topped Pitcher Plant | Direct sun (at least 4-6 hours) | Keep constantly moist to wet — sit pots in 2–5 cm of standing water during the growing season | Mildly toxic to pets |
| Whitley's Speedwell | Direct sun (at least 4-6 hours) | Every 10–14 days during active growth; minimal in winter | Pet-safe |
| Whorled Heath | Direct sun (at least 4-6 hours) | Infrequent once established; drought-tolerant | Mildly toxic to pets |
| Whorled Milkweed | Direct sun (at least 4-6 hours) | Water to establish, then rarely; highly drought-tolerant once settled | Toxic to pets |
| Whorled Rosinweed | Bright indirect light (just back from a sunny window) | Every 1-2 weeks once established | Pet-safe |
| Whorled Solomon's Seal | Medium indirect light (a couple of metres from a window) | Every 5–7 days during the growing season; reduce in autumn | Mildly toxic to pets |
| Whorled Water Milfoil | Direct sun (at least 4-6 hours) | Permanently submerged | Pet-safe |
| Wickwar Flame heather | Direct sun (at least 4-6 hours) | Weekly during establishment, then as needed | Pet-safe |
| Wide Brim Hosta | Low light (north window or shaded room) | When the top 2-3cm of soil is dry, roughly every 5-7 days during active growth | Toxic to pets |
| Wide-leaved Grape Hyacinth | Bright indirect light (just back from a sunny window) | Every 7–10 days in spring; dry over summer | Mildly toxic to pets |
| Wide-Leaved Sea Lavender | Direct sun (at least 4-6 hours) | Every 2–3 weeks when established | Pet-safe |
| Wild Blue Phlox | Medium indirect light (a couple of metres from a window) | Weekly; keep soil evenly moist | Mildly toxic to pets |
| Wild Cherry Bonsai | Direct sun (at least 4-6 hours) | When the top 2 cm of soil begins to dry, often daily in summer | Toxic to pets |
| Wild Crabapple Bonsai | Direct sun (at least 4-6 hours) | When the top 2-3 cm is dry, often daily in summer and much less in winter dormancy | Toxic to pets |
| Wild Edric Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly in the growing season, more in heat or sandy soil | Pet-safe |
| Wild Gazania | Direct sun (at least 4-6 hours) | Every 10–14 days (very drought-tolerant once established) | Mildly toxic to pets |
| Wild jasmine | Bright indirect light (just back from a sunny window) | Once or twice a week during active growth; reduce in winter | Pet-safe |
| Wild Lupine | Direct sun (at least 4-6 hours) | Water to establish, then rarely; it is drought-tolerant once settled | Toxic to pets |
| Wild maracuja | Direct sun (at least 4-6 hours) | Every 7–14 days; drought-tolerant once established | Mildly toxic to pets |
| Wild nemesia | Direct sun (at least 4-6 hours) | Every 7–14 days once established; more frequently when young | Pet-safe |
| Wild pansy | Bright indirect light (just back from a sunny window) | Every 5–7 days; keep soil evenly moist but not wet | Pet-safe |
| Wild Quinine | Direct sun (at least 4-6 hours) | Low — drought-tolerant once established | Mildly toxic to pets |
| Wild Rose | Direct sun (at least 4-6 hours) | Weekly while establishing, then rarely once mature | Pet-safe |
| Wild Senna | Bright indirect light (just back from a sunny window) | Weekly in dry periods; tolerates brief flooding | Mildly toxic to pets |
| Wild Teasel | Bright indirect light (just back from a sunny window) | Regular during establishment; tolerates winter wet | Mildly toxic to pets |
| Wildeve Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly while growing, increasing in heat and on free-draining soils | Pet-safe |
| Wildfire Black Tupelo | Direct sun (at least 4-6 hours) | Weekly during establishment; moderate once mature | Mildly toxic to pets |
| William Buchanan heath | Bright indirect light (just back from a sunny window) | Moderate; water regularly, especially during flowering and in dry summers | Pet-safe |
| William Shakespeare 2000 Rose | Direct sun (at least 4-6 hours) | Deeply once or twice weekly through the growing season, more in heat | Pet-safe |
| Williams rhododendron | Bright indirect light (just back from a sunny window) | Every 7–10 days in growing season; reduce to monthly in winter | Toxic to pets |
| Willow Gentian | Medium indirect light (a couple of metres from a window) | Regular; maintain consistently moist soil throughout the growing season | Mildly toxic to pets |
| Willow Oak | Direct sun (at least 4-6 hours) | Moderate; water weekly when young; tolerates periodic flooding once established | Mildly toxic to pets |
| Wilson Spruce | Direct sun (at least 4-6 hours) | Weekly when young; established trees are drought-tolerant | Pet-safe |
| Wiltoni Juniper | Direct sun (at least 4-6 hours) | Every 7-10 days in year one, then rarely | Mildly toxic to pets |
| Wine Cups Babiana | Direct sun (at least 4-6 hours) | Water during active growth (autumn to spring); cease completely once foliage yellows | Mildly toxic to pets |
| Winter Aconite | Medium indirect light (a couple of metres from a window) | Relies on natural rainfall; keep soil moist during active growth | Toxic to pets |
| Winter Gem Boxwood | Medium indirect light (a couple of metres from a window) | When the top 5 cm of soil is dry, about weekly while establishing | Toxic to pets |
| Winter Glow Bergenia | Medium indirect light (a couple of metres from a window) | Every 7–14 days during the growing season; very little in winter | Pet-safe |
| Winter Gold Mugo Pine | Direct sun (at least 4-6 hours) | Weekly for the first two seasons; established plants every 2-3 weeks in drought | Mildly toxic to pets |
| Winter heath | Direct sun (at least 4-6 hours) | Established plants: every 2–3 weeks in dry spells; new plants: weekly for the first season | Pet-safe |
| Winter Heath Springwood White | Direct sun (at least 4-6 hours) | Weekly during dry spells; drought-tolerant once established | Mildly toxic to pets |
| Winter Iris | Direct sun (at least 4-6 hours) | Low — drought-tolerant; water sparingly in summer | Toxic to pets |
| Winterberry Holly 'Winter Red' | Direct sun (at least 4-6 hours) | Keep consistently moist; water regularly in dry spells | Toxic to pets |
| Wintergreen Barberry | Bright indirect light (just back from a sunny window) | When the top 5-8 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Wintersweet | Direct sun (at least 4-6 hours) | Water in dry spells; moderate once established | Mildly toxic to pets |
| Wintertime prickly heath | Bright indirect light (just back from a sunny window) | Regular; keep evenly moist | Toxic to pets |
| Wisley 2008 Rose | Direct sun (at least 4-6 hours) | Deeply once or twice a week in the growing season; more in heat or sandy soil | Pet-safe |
| Wisley Gaultheria | Medium indirect light (a couple of metres from a window) | Every 5–7 days in the growing season; less in cool winters | Mildly toxic to pets |
| Wisley Pearl Gaultheria | Bright indirect light (just back from a sunny window) | Regularly; keep soil evenly moist | Toxic to pets |
| Wisteria 'Amethyst Falls' | Direct sun (at least 4-6 hours) | Weekly while establishing; water in summer drought | Toxic to pets |
| Wisteria floribunda | Direct sun (at least 4-6 hours) | Water deeply in dry spells, particularly through bud development; mature plants tolerate some drought | Toxic to pets |
| Wisteria floribunda 'Multijuga' | Direct sun (at least 4-6 hours) | Water deeply in dry weather, especially during flowering and bud set; established plants tolerate moderate drought | Toxic to pets |
| Wisteria sinensis | Direct sun (at least 4-6 hours) | Water deeply during dry spells, especially while flower buds form; established plants are fairly drought-tolerant | Toxic to pets |
| Wisteria sinensis 'Alba' | Direct sun (at least 4-6 hours) | Water deeply during dry spells, especially as buds form; established plants tolerate some drought | Toxic to pets |
| Witch Hazel | Bright indirect light (just back from a sunny window) | Keep evenly moist; water in dry spells | Mildly toxic to pets |
| Witchgrass | Direct sun (at least 4-6 hours) | Rainfall sufficient in most climates; supplemental water only if very dry | Pet-safe |
| Wolf Eyes Kousa Dogwood | Bright indirect light (just back from a sunny window) | Weekly during establishment; every 10–14 days once mature | Mildly toxic to pets |
| Wood Anemone | Medium indirect light (a couple of metres from a window) | Weekly during spring growth; none required during summer dormancy | Toxic to pets |
| Wood Avens | Medium indirect light (a couple of metres from a window) | Low to moderate — rain-fed in shade | Pet-safe |
| Wood Club-rush | Medium indirect light (a couple of metres from a window) | Permanently moist to wet; tolerates shallow standing water | Pet-safe |
| Wood Forget-me-not | Medium indirect light (a couple of metres from a window) | Moderate; keep soil moist but well-drained | Pet-safe |
| Wood Melic | Medium indirect light (a couple of metres from a window) | Keep evenly moist while establishing; tolerates dry shade once rooted | Mildly toxic to pets |
| Wood Melick | Medium indirect light (a couple of metres from a window) | Infrequently; drought-tolerant under shade | Pet-safe |
| wood small-reed | Direct sun (at least 4-6 hours) | Drought-tolerant once established; occasional deep watering in first season | Pet-safe |
| Wood Vetch | Medium indirect light (a couple of metres from a window) | Low to moderate — prefers moderate moisture with periods of drying | Mildly toxic to pets |
| Woodland Sage | Direct sun (at least 4-6 hours) | Low to moderate; drought tolerant once established | Pet-safe |
| Woodland Sunflower | Medium indirect light (a couple of metres from a window) | Every 2–3 weeks; drought-tolerant once established | Pet-safe |
| Woodsia ilvensis | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days | Mildly toxic to pets |
| Woodsia obtusa | Medium indirect light (a couple of metres from a window) | When the top 2-3 cm of soil is dry, roughly every 5-8 days | Mildly toxic to pets |
| Woodwardia fimbriata | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist to wet; check every 2-4 days in growth | Mildly toxic to pets |
| Woodwardia unigemmata | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the top 2-3 cm of soil begins to dry, roughly every 4-7 days in growth | Mildly toxic to pets |
| Woolly Jerusalem Sage | Direct sun (at least 4-6 hours) | Low — once every 2–3 weeks once established; minimal in winter | Mildly toxic to pets |
| Woolly Rock Jasmine | Direct sun (at least 4-6 hours) | Moderate in summer; very little in winter | Pet-safe |
| Woolly yarrow | Direct sun (at least 4-6 hours) | Every 2–3 weeks once established; minimal supplemental watering needed | Mildly toxic to pets |
| Worplesdon Sweetgum | Direct sun (at least 4-6 hours) | Weekly during the first 3 years; supplemental watering in dry summers | Mildly toxic to pets |
| Wulfen's Alyssum | Direct sun (at least 4-6 hours) | Every 14–21 days during growing season; very little in winter | Pet-safe |
| Wych Elm Bonsai | Direct sun (at least 4-6 hours) | When the top 2 cm of soil begins to dry, often daily in summer | Mildly toxic to pets |
| Xalapa Sage | Direct sun (at least 4-6 hours) | Allow the top 5 cm of soil to dry between waterings | Pet-safe |
| Yakushima Rhododendron | Bright indirect light (just back from a sunny window) | Weekly during dry weather; do not allow to dry out in summer or before frost | Toxic to pets |
| Yakushima Rhododendron 'Yaku Princess' | Bright indirect light (just back from a sunny window) | About weekly, more during heat; water when the top 2-3 cm of soil is dry | Toxic to pets |
| Yarrow 'Moonshine' | Direct sun (at least 4-6 hours) | When the top few centimeters of soil are dry, roughly every 7-14 days | Mildly toxic to pets |
| Yellow Archangel | Medium indirect light (a couple of metres from a window) | Every 7–14 days; drought-tolerant once established in shade | Mildly toxic to pets |
| Yellow Azalea | Bright indirect light (just back from a sunny window) | Weekly during dry spells; established plants are reasonably drought-tolerant but flower best with consistent moisture | Toxic to pets |
| Yellow Barrenwort | Medium indirect light (a couple of metres from a window) | Weekly during first two seasons; established plants are drought-tolerant and rarely need supplemental watering | Mildly toxic to pets |
| Yellow Birch | Direct sun (at least 4-6 hours) | Consistently moist; water deeply 1-2 times per week during establishment and in dry spells | Pet-safe |
| Yellow Clintonia | Low light (north window or shaded room) | Twice weekly in dry spells; maintain even soil moisture throughout the growing season | Pet-safe |
| Yellow Clivia | Bright indirect light (just back from a sunny window) | When top 3-4 cm of soil is dry, roughly every 7-10 days in growth | Toxic to pets |
| Yellow coneflower | Direct sun (at least 4-6 hours) | Every 1–2 weeks during establishment; every 2–4 weeks once established | Pet-safe |
| Yellow Crocus | Direct sun (at least 4-6 hours) | Very low — water once at planting; rainfall sufficient during growth; completely dry in summer | Mildly toxic to pets |
| Yellow Fairybells | Medium indirect light (a couple of metres from a window) | Regular; maintain consistent moisture | Mildly toxic to pets |
| Yellow False Jasmine | Bright indirect light (just back from a sunny window) | Water every 7-10 days during the growing season; reduce to every 2-3 weeks once established and dormancy slows growth | Toxic to pets |
| Yellow Fawnlily | Medium indirect light (a couple of metres from a window) | Consistently moist during active growth (late winter to late spring); minimal after dormancy | Mildly toxic to pets |
| Yellow Firethorn | Direct sun (at least 4-6 hours) | When the top 5 cm of soil is dry, roughly every 10-14 days | Mildly toxic to pets |
| Yellow Foxglove | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly weekly in dry spells | Toxic to pets |
| Yellow Gentian | Direct sun (at least 4-6 hours) | Regular; keep evenly moist during the growing season — never allow to fully dry out | Mildly toxic to pets |
| Yellow Giant Hyssop | Bright indirect light (just back from a sunny window) | Every 7–10 days during the growing season; minimal in winter | Pet-safe |
| Yellow Glacier Lily | Medium indirect light (a couple of metres from a window) | Regular during spring growth; reduce sharply after dormancy | Mildly toxic to pets |
| Yellow Heron's Bill | Direct sun (at least 4-6 hours) | Water sparingly every 10-14 days in summer; keep almost completely dry from late autumn to early spring | Mildly toxic to pets |
| Yellow Horned Poppy | Direct sun (at least 4-6 hours) | Occasionally during dry spells only | Toxic to pets |
| Yellow Ice Plant | Direct sun (at least 4-6 hours) | Every 2–3 weeks during the growing season; minimal to none in winter | Pet-safe |
| Yellow Ice Plant | Direct sun (at least 4-6 hours) | When the top 3 cm of soil is dry, roughly every 7–14 days in summer; very little supplemental water needed once established | Mildly toxic to pets |
| Yellow Loosestrife | Medium indirect light (a couple of metres from a window) | Regularly, keeping soil consistently moist | Mildly toxic to pets |
| Yellow Marliac Water Lily | Direct sun (at least 4-6 hours) | Permanently aquatic — crown submerged 15–75 cm (6–30 in) below water surface | Pet-safe |
| Yellow Monkeyflower | Bright indirect light (just back from a sunny window) | Keep soil permanently wet; never allow to dry out | Pet-safe |
| Yellow Moth Orchid | Bright indirect light (just back from a sunny window) | When the bark is nearly dry, typically every 7-10 days | Pet-safe |
| Yellow Mountain Heath | Bright indirect light (just back from a sunny window) | Regular — keep consistently moist | Mildly toxic to pets |
| Yellow Mountain Saxifrage | Direct sun (at least 4-6 hours) | Every 2–4 days during the growing season; keep consistently moist | Pet-safe |
| Yellow Pimpernel | Medium indirect light (a couple of metres from a window) | High; keep consistently moist | Mildly toxic to pets |
| Yellow Pitaya | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, roughly every 7-10 days in summer; every 2-4 weeks in winter | Pet-safe |
| Yellow Pitcher Plant | Direct sun (at least 4-6 hours) | Keep permanently wet; stand the pot in 1-3 cm of water during the growing season (tray method) | Pet-safe |
| Yellow Prairie Wild Indigo | Direct sun (at least 4-6 hours) | Every 2 weeks in year 1–2; essentially drought independent once established | Toxic to pets |
| Yellow Rain Lily | Direct sun (at least 4-6 hours) | A dry period of 2-3 weeks followed by generous watering triggers flowers; moderate moisture otherwise | Toxic to pets |
| Yellow Rattle | Direct sun (at least 4-6 hours) | Rain-fed; no supplemental irrigation needed once sown into a meadow | Mildly toxic to pets |
| Yellow Tower Cactus | Direct sun (at least 4-6 hours) | When the top 3-5 cm of soil is dry, every 7-14 days in spring and summer; every 4-6 weeks in autumn; once monthly or less in winter | Pet-safe |
| Yellow Trillium | Medium indirect light (a couple of metres from a window) | Regular during spring growing season; reduced once foliage dies back in summer. | Mildly toxic to pets |
| Yellow Trout Lily | Medium indirect light (a couple of metres from a window) | Water regularly in spring; allow to dry naturally after dormancy sets in | Mildly toxic to pets |
| Yellow Trumpet Creeper | Direct sun (at least 4-6 hours) | Every 7–10 days during establishment; drought-tolerant once mature | Mildly toxic to pets |
| Yellow Water Lily | Direct sun (at least 4-6 hours) | Permanently aquatic — crown submerged 15–45 cm (6–18 in) below water surface | Pet-safe |
| Yellow Whitlow Grass | Direct sun (at least 4-6 hours) | Low — allow soil to dry between waterings | Mildly toxic to pets |
| Yellow Whitlowgrass | Direct sun (at least 4-6 hours) | Every 10–14 days in the growing season; minimal in winter | Pet-safe |
| Yellow Wild Indigo | Direct sun (at least 4-6 hours) | Weekly the first season; rarely thereafter once established | Toxic to pets |
| Yellow Wood Anemone | Medium indirect light (a couple of metres from a window) | Weekly during spring growth; dormant and dry in summer | Toxic to pets |
| Yellow Woodland Violet | Medium indirect light (a couple of metres from a window) | Weekly; maintain evenly moist soil throughout spring and summer | Mildly toxic to pets |
| Yellow-flowered Sage | Direct sun (at least 4-6 hours) | Every 7-10 days during active growth; very sparingly in winter | Pet-safe |
| Yellow-Twig Dogwood | Bright indirect light (just back from a sunny window) | Regularly; keep soil consistently moist | Pet-safe |
| Yellow-wort | Direct sun (at least 4-6 hours) | Rarely — water only during severe drought | Mildly toxic to pets |
| Yesterday-Today-and-Tomorrow | Bright indirect light (just back from a sunny window) | Keep evenly moist; water when the top of the soil starts to dry, roughly 1-2x per week in growth. | Toxic to pets |
| Yew Bonsai | Bright indirect light (just back from a sunny window) | When the top 2-3 cm is dry, typically every 2-4 days in summer and less in winter | Toxic to pets |
| Yoshino Cherry | Direct sun (at least 4-6 hours) | Water young trees weekly in dry weather; established trees need little | Toxic to pets |
| Young's Weeping Birch | Bright indirect light (just back from a sunny window) | Weekly during establishment and dry spells; every 2 weeks once mature | Pet-safe |
| Yulan Magnolia | Direct sun (at least 4-6 hours) | Weekly when young; established trees need water during prolonged dry spells | Pet-safe |
| Yuletide Sasanqua Camellia | Bright indirect light (just back from a sunny window) | Every 5-7 days in summer; reduce in winter but do not let dry out | Pet-safe |
| Yunnan Cypress | Direct sun (at least 4-6 hours) | Regular during establishment; drought-tolerant once mature | Pet-safe |
| Zamia Pumila | Bright indirect light (just back from a sunny window) | When the top 4-5 cm of soil is dry, roughly every 10-14 days | Toxic to pets |
| Zantedeschia 'Black Star' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zantedeschia 'Captain Safari' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist in growth and bloom; keep dry over winter dormancy | Toxic to pets |
| Zantedeschia 'Captain Tendens' | Bright indirect light (just back from a sunny window) | Keep soil evenly moist in growth and bloom; keep dry during winter dormancy | Toxic to pets |
| Zantedeschia 'Captain Violetta' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zantedeschia 'Crystal Blush' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, watering when the top 2-3 cm is dry (often every 4-7 days) | Toxic to pets |
| Zantedeschia 'Edge of Night' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, watering when the top 2-3 cm of soil dries; reduce sharply as foliage fades | Toxic to pets |
| Zantedeschia 'Flame' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, watering when the top 2-3 cm of soil is dry; reduce as foliage dies back | Toxic to pets |
| Zantedeschia 'Hot Chocolate' | Bright indirect light (just back from a sunny window) | Keep evenly moist during growth, watering as the top 2-3 cm of soil dries; cut back as it goes dormant | Toxic to pets |
| Zantedeschia 'Mango' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zantedeschia 'Picasso' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zantedeschia 'Schwarzwalder' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zantedeschia albomaculata | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zantedeschia elliottiana | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry during active growth, roughly every 5-7 days | Toxic to pets |
| Zantedeschia jucunda | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zantedeschia pentlandii | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of soil is dry, roughly every 5-7 days in active growth | Toxic to pets |
| Zebra Grass | Direct sun (at least 4-6 hours) | Weekly for the first season; every 2–3 weeks once established | Pet-safe |
| Zebrinus Zebra Grass | Direct sun (at least 4-6 hours) | Weekly while establishing, then during dry spells; appreciates steady moisture | Mildly toxic to pets |
| Zephirine Drouhin Rose | Direct sun (at least 4-6 hours) | Deeply once a week in the growing season; more in heat or during establishment | Pet-safe |
| Zigzag Clover | Medium indirect light (a couple of metres from a window) | Moderate; tolerates short dry spells once established | Pet-safe |
| Zigzag Goldenrod | Medium indirect light (a couple of metres from a window) | Keep soil consistently moist; water weekly in dry spells | Mildly toxic to pets |
| Zigzag Iris | Medium indirect light (a couple of metres from a window) | Consistently moist to wet | Mildly toxic to pets |
| Zinnia | Direct sun (at least 4-6 hours) | Deep watering once a week | Pet-safe |
| Zinnia 'Benary's Giant' | Direct sun (at least 4-6 hours) | When top 3-4 cm of soil is dry, roughly every 4-6 days in summer | Pet-safe |
| Zinnia 'Profusion' | Direct sun (at least 4-6 hours) | When top 2-3 cm of soil is dry, every 4-7 days; containers more often | Pet-safe |
| Zinnia elegans 'Benary's Giant Coral' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 4-7 days | Pet-safe |
| Zinnia elegans 'Profusion Cherry' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 5-7 days | Pet-safe |
| Zinnia elegans 'Zahara Starlight Rose' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 5-7 days | Pet-safe |
| Zinnia haageana 'Old Mexico' | Direct sun (at least 4-6 hours) | When the top 3-4 cm of soil is dry, about every 5-7 days | Pet-safe |
| Zois's Bellflower | Direct sun (at least 4-6 hours) | Low to moderate — water sparingly; allow to nearly dry between waterings | Mildly toxic to pets |
| Zoys's Bellflower | Direct sun (at least 4-6 hours) | Allow soil to dry between waterings; very sparingly in winter | Pet-safe |
| Zulu Spurflower | Medium indirect light (a couple of metres from a window) | Moderate — water twice weekly in containers; less frequently in ground | Mildly toxic to pets |
| Zygopetalum 'Artur Elle' | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, every 5-7 days, easing back as pseudobulbs mature | Pet-safe |
| Zygopetalum 'Blue Eyes' | Bright indirect light (just back from a sunny window) | Keep evenly moist, watering when the surface starts to dry, roughly every 4-6 days | Pet-safe |
| Zygopetalum 'Redvale' | Bright indirect light (just back from a sunny window) | When the top 2-3 cm of mix is approaching dry, roughly every 5-7 days | Pet-safe |
| Zygopetalum 'Titanic' | Bright indirect light (just back from a sunny window) | Keep evenly moist during growth, every 5-7 days, reducing as pseudobulbs mature | Pet-safe |
| Zygopetalum intermedium | Bright indirect light (just back from a sunny window) | Keep evenly moist during growth, every 5-7 days, reducing once pseudobulbs mature | Pet-safe |
| Zygopetalum mackaii | Bright indirect light (just back from a sunny window) | Keep evenly moist in growth, every 5-7 days, easing off after the pseudobulbs mature | Pet-safe |
| Zygopetalum Orchid | Bright indirect light (just back from a sunny window) | Roughly every 3-7 days; more often in warm, active growth, less in winter | Mildly toxic to pets |
This list is not hand-picked for looks. It is plants in our library categorised as flowering houseplants, drawn from Growli's structured plant-care library so the selection is consistent and checkable. 4791 plants qualify today.
Growli currently lists 4791 plants that meet the criterion (plants in our library categorised as flowering houseplants). The list updates as the plant-care library grows; each entry links to a full care guide.
Not necessarily — this list is selected by plants in our library categorised as flowering houseplants, not by pet safety. Each plant is tagged with its pet-safety status below, and links to a full ASPCA-sourced pet-safety guide. If you have pets, see the dedicated best pet-safe houseplants list.
Once you have shortlisted a plant, the next questions are watering and soil. These are the guides searched most this season: