1 named cultivar

‘Giant Form’Giant Formosan Lily

bulb corm tuber

osan Lily

Lilium formosanum

The Story

Plant Bio

Lilium formosanum, Formosa lily, is a tall bulbous perennial from Taiwan, reaching four to seven feet. Narrow lance-shaped leaves clothe slender upright stems, and enormous trumpet flowers over six inches long open in late summer and autumn, pure white inside and streaked wine-purple on the outside, with a powerful evening scent.

Every part of a true lily is lethally toxic to cats — pollen brushed onto fur, a chewed leaf, even water from the vase causes fatal kidney failure. Do not have this plant in a home with cats. In the garden it is remarkable: it flowers in its first or second year from seed, unusually fast for a lily, and the upright seedpods dry well for arrangements.

Uses & Benefits:

Enormous white trumpets streaked wine-purple outside, on tall stems in late summer.

Flowers from seed within a year or two, which makes it far cheaper to establish than most lilies.

Night-flying moths work the scented trumpets, and the dried pods hold structure into winter.

Essentials

At a Glance

Plant Type

Bulb Corm Tuber

Height

66 inches

Width

30 inches

Light

Full Sun, Partial Sun

Zones

6, 7, 8, 9

Water

Moderate

Humidity

Moderate

Lifespan

Perennial

Native To

Taiwan

Toxicity

Fatally toxic to cats; all parts

Planting

How to Grow

Do not grow it where cats have access.
Plant bulbs in full sun to partial shade.
Give it deep, freely draining soil.
Stake tall stems in exposed positions.
Leave the upright seedpods for winter interest.
Expect flowers within a year or two from seed.

Pro Tip

It flowers within a year or two from seed, which almost no other lily does — so it can be raised from a packet rather than bought as bulbs.

Keep It Thriving

Care Guide

Do

Keep it away from cats entirely 🐈
Give it deep, well-drained soil 🌱
Stake tall stems if exposed 🪝
Leave seedpods for drying 🌾

Don't

Bring it into a home with cats ❌
Plant it in wet or heavy soil ❌
Cut the leaves off green ❌

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Enjoy
Sow

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Tall late-season accent in a sunny borderEvening-scented planting near a seatCutting garden for trumpets and dried pods

Companion Plants

Japanese Anemone Salvia AsterMuhly Grass Sedum

Multiply

Propagation Methods

Good to Know

Common Questions

osan Lily questions

What zones can osan Lily grow in?

osan Lily is hardy in USDA Zones 6–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is osan Lily deer resistant?

Not reliably. Deer may browse osan Lily, especially tender spring growth — plan on repellents or fencing where pressure is high.

When does osan Lily bloom?

osan Lily typically blooms in late summer to fall through late summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does osan Lily need full sun?

osan Lily does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.