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Plant care

Water Speedwell care

Veronica anagallis-aquatica

Also called Water Speedwell, Blue Water Speedwell.

RHS H6USDA 4–9Pet-safeIndoor 20–60 cm tall

Watering rhythm

Direct sun (at least 4-6 hours)

Permanently wet to shallow submersion

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Light

Direct sun (at least 4-6 hours)

Soil

Wet loam, clay, or silt

Humidity

55–100%

Temp

-15–28°C

Pet safety

Pet-safe

Mature size

20–60 cm tall

Care at a glance

Light

Most houseplants will scorch where water speedwell thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Grows best in full sun to partial shade. Open stream banks and sunny pond margins suit it well. In partial shade it still flowers, though more sparsely. It naturally colonises exposed, open waterside habitats. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

Aim for permanently wet to shallow submersion for water speedwell, but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Grows in saturated mud, very shallow water up to 10 cm, or in damp soil at the water's edge. Also suitable as a submerged aquatic in slow or still water. Tolerates seasonal flooding and fluctuating water levels typical of natural stream habitats.

Soil and pot

Water Speedwell grows best in wet loam, clay, or silt. Accepts a wide range of wet substrates from heavy clay to sandy loam, provided they remain saturated. No special compost or amendments needed — natural waterside soil or pond silt is ideal. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Water Speedwell sits happiest at around 55–100% humidity and -15–28°C (5–82°F). Adapted to riparian environments where ambient humidity is consistently high. In garden settings at pond margins, no additional humidity management is required. Dislikes dry, droughty conditions. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed water speedwell sparingly. No feeding required or recommended. Plants grow vigorously in the low-to-moderate nutrient levels typical of natural waterways. Excessive nutrients promote overly lush but weak growth susceptible to disease. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on water speedwell in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Self-seeding becoming weedy — Water Speedwell self-seeds prolifically and can colonise beyond its intended planting area. Deadhead spent flower racemes before seed sets if spread needs to be controlled in a managed pond or garden.
  • Powdery mildew in stagnant air — Plants in warm, sheltered positions with poor air circulation may develop powdery mildew on leaves in late summer. Thin out congested growth to improve airflow; the plant typically regenerates healthy growth quickly.
  • Frost die-back of top growth — Top growth often dies back in hard winters, but the rootstock re-sprouts reliably in spring. Self-sown seedlings also overwinter and fill gaps. No protection is normally needed in UK climates.

Propagation

Self-seeds readily around parent plants — collect and sow seed in autumn in wet compost. Stem cuttings taken in spring or summer root readily in wet soil or even a glass of water. Division of established clumps in spring is also straightforward. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Water Speedwell is pet-safe. Veronica anagallis-aquatica (family Plantaginaceae, formerly Scrophulariaceae) is not individually listed by ASPCA. Veronicas as a group have no documented toxic principle for pets or humans. The plant has a long history of use in traditional European herbal medicine with no reported toxicity concerns. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Water Speedwell care — frequently asked questions

What is Water Speedwell?

Water Speedwell (Veronica anagallis-aquatica) is a flowering plant with a semi-erect to sprawling semi-aquatic perennial or biennial. forms leafy stems with opposite, clasping lanceolate leaves and axillary flower racemes. self-seeds freely and can form loose colonies. growth habit, reaching 20–60 cm tall; spread 30–50 cm at maturity. Water Speedwell is a native European aquatic or semi-aquatic perennial producing slender racemes of tiny pale blue to lilac flowers along stream banks, pond margins, and wet ditches throughout summer. A good habitat plant for wildlife ponds, it provides nectar for small bees and hoverflies.

How much light does water speedwell need?

Water Speedwell grows best in direct sun (at least 4-6 hours). Grows best in full sun to partial shade. Open stream banks and sunny pond margins suit it well. In partial shade it still flowers, though more sparsely. It naturally colonises exposed, open waterside habitats.

How often should I water water speedwell?

Water water speedwell permanently wet to shallow submersion. Grows in saturated mud, very shallow water up to 10 cm, or in damp soil at the water's edge. Also suitable as a submerged aquatic in slow or still water. Tolerates seasonal flooding and fluctuating water levels typical of natural stream habitats. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is water speedwell toxic to cats and dogs?

Water Speedwell is pet-safe. Veronica anagallis-aquatica (family Plantaginaceae, formerly Scrophulariaceae) is not individually listed by ASPCA. Veronicas as a group have no documented toxic principle for pets or humans. The plant has a long history of use in traditional European herbal medicine with no reported toxicity concerns.

What USDA hardiness zone does water speedwell grow in?

Water Speedwell is rated for USDA zone 4–9 and RHS hardiness H6. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Water Speedwell deep-dive guides

Every aspect of water speedwell care, each with its own calibrated guide:

Featured in these plant shortlists

Water Speedwell qualifies for 10 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

  • Best pet-safe houseplants — Houseplants the ASPCA lists as non-toxic to cats and dogs — every one verified against the ASPCA toxic and non-toxic plant list.
  • Best humidity-loving houseplants — Houseplants that thrive in a bathroom, kitchen, or by a humidifier — selected by documented humidity preference.
  • Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
  • Best pet-safe flowering plants — Flowering houseplants the ASPCA lists as non-toxic to cats and dogs — colour and blooms in a pet home, without the worry.
  • Best pet-safe plants for bright light — Non-toxic to cats and dogs and happy in a bright, sunny spot — safe plants for your best-lit windowsill.
  • Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
  • Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
  • Best fast-growing houseplants — Houseplants documented as fast or vigorous growers — quick to fill a pot, cover a pole or trail down a shelf.
  • Best cat-safe plants — Houseplants the ASPCA lists as non-toxic to cats (and dogs) — safe greenery for a home with a curious cat.
  • Best dog-safe plants — Houseplants the ASPCA lists as non-toxic to dogs (and cats) — safe greenery for a home with a curious dog.
  • Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Water Speedwell is also commonly called Water Speedwell or Blue Water Speedwell.