Plant care
Formosa Lily (Taiwan Lily) care
Lilium formosanum
Also called Formosa Lily, Taiwan Lily.
Watering rhythm
Direct sun (at least 4-6 hours)
2-3 times per week in active growth
Light
Direct sun (at least 4-6 hours)
Soil
Well-drained, humus-rich loam
Humidity
40–70%
Temp
10–28°C
Pet safety
Toxic to pets
Mature size
90–180 cm tall (3–6 ft)
Care at a glance
Light
Most houseplants will scorch where formosa lily thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Requires at least 6 hours of direct sun daily. Plant in full sun for best flowering and stem strength. Tolerates partial afternoon shade in hotter climates to prevent leaf scorch. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.
Watering
Aim for 2-3 times per week in active growth for formosa lily, 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. Keep soil evenly moist during spring and summer growth. Reduce watering after flowering and allow to dry slightly during dormancy. Never allow standing water around bulbs, which causes rot.
Soil and pot
Formosa Lily grows best in well-drained, humus-rich loam. Prefers slightly acidic to neutral pH (6.0–7.0). Amend heavy clay soils with grit and organic matter. Excellent drainage is critical — bulbs rot readily in waterlogged conditions. 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
Formosa Lily sits happiest at around 40–70% humidity and 10–28°C (50–82°F). Adaptable to a range of humidity levels. In dry climates, mulch around the base to retain soil moisture and moderate temperature extremes. Good air circulation helps prevent fungal diseases. If you keep the room above 10–28°C 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 formosa lily sparingly. Apply a balanced bulb fertiliser (e.g. 10-10-10) in early spring as shoots emerge, then switch to a low-nitrogen, high-potassium feed monthly through bud set. Cease feeding after flowering. 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 formosa lily in the Growli community. Each is annotated with the most common cause so you know where to start.
- Botrytis (gray mold) — Gray fuzzy lesions on leaves and buds in cool, humid conditions. Improve air circulation, remove affected material promptly, and avoid wetting foliage when watering.
- Lily beetle (Lilioceris lilii) — Scarlet beetles and their larvae skeletonize leaves rapidly. Inspect undersides of leaves regularly and hand-pick or treat with neem oil or an appropriate insecticide.
- Basal rot (Fusarium oxysporum) — Bulb decay at the base, causing yellowing and collapse. Plant in well-drained soil, avoid wounding bulbs at planting, and discard any soft or discoloured bulbs before use.
Propagation
Easiest from seed — germinates in 2–3 weeks and flowers within 1 year (unusually fast for a lily). Also propagates from bulb scales or offsets detached in autumn. Bulbils sometimes form on stems. 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
Formosa Lily is toxic to pets. ASPCA lists Lilium species as severely toxic to cats. Ingestion of any part — including pollen, leaves, or water from the vase — can cause acute kidney failure in cats and may be fatal without immediate veterinary treatment. Mildly toxic to dogs and horses (GI upset). Keep away from all cats. 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.
Formosa Lily care — frequently asked questions
What is the common name for Lilium formosanum?
Lilium formosanum is most commonly called Formosa Lily, but it is also known as Formosa Lily, Taiwan Lily. The names refer to the same species, so care instructions for Formosa Lily apply identically to anything sold as Taiwan Lily.
How much light does formosa lily need?
Formosa Lily grows best in direct sun (at least 4-6 hours). Requires at least 6 hours of direct sun daily. Plant in full sun for best flowering and stem strength. Tolerates partial afternoon shade in hotter climates to prevent leaf scorch.
How often should I water formosa lily?
Water formosa lily 2-3 times per week in active growth. Keep soil evenly moist during spring and summer growth. Reduce watering after flowering and allow to dry slightly during dormancy. Never allow standing water around bulbs, which causes rot. 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 formosa lily toxic to cats and dogs?
Formosa Lily is toxic to pets. ASPCA lists Lilium species as severely toxic to cats. Ingestion of any part — including pollen, leaves, or water from the vase — can cause acute kidney failure in cats and may be fatal without immediate veterinary treatment. Mildly toxic to dogs and horses (GI upset). Keep away from all cats.
What USDA hardiness zone does formosa lily grow in?
Formosa Lily is rated for USDA zone 5–9 and RHS hardiness H4. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.
Formosa Lily deep-dive guides
Every aspect of formosa lily care, each with its own calibrated guide:
- Formosa Lily watering schedule
- Formosa Lily light requirements
- Best soil mix for formosa lily
- Formosa Lily fertilizing guide
- When to repot formosa lily
- How to propagate formosa lily
- Formosa Lily growth rate & size
- Formosa Lily cold hardiness
- Formosa Lily temperature & humidity
- Is formosa lily toxic to cats & dogs?
- Is formosa lily toxic to cats?
- Is formosa lily toxic to dogs?
- Getting formosa lily to bloom
Featured in these plant shortlists
Formosa Lily qualifies for 6 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:
- Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
- Houseplants toxic to cats & dogs — The common houseplants the ASPCA lists as toxic to cats and dogs — the ones to keep out of reach, each with its symptoms and a safe alternative.
- 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 fragrant houseplants — Indoor plants with scented flowers or aromatic foliage — greenery you can smell, selected from our care library.
- Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more
Related guides
Formosa Lily is also commonly called Formosa Lily or Taiwan Lily.