Species

Arisaema serratumJapanese Jack-in-the-Pulpit

1 other cultivar

‘Mt Fuji Form’Mt Fuji Form Japanese Cobra Lily

perennial

Ulleung Treasure Japanese Cobra Lily

Arisaema serratum 'Ulleung Treasure'

The Story

Plant Bio

Arisaema serratum, commonly known as Japanese Cobra Lily, is a tuberous perennial. It features a unique flower structure with a hooded spathe, often striped purple-brown and green, surrounding a club-like spadix. Its large, compound leaves are also highly ornamental.

'Ulleung Treasure' is a prized selection from Ulleung Island, Korea, noted for its robust growth and striking trifoliate leaves heavily patterned with silver-white variegation.

Uses & Benefits:

Adds exotic appeal with its striking flower structure in shaded gardens.

Prefers moist, well-drained soils, reducing the need for frequent watering.

Provides habitat for woodland insects and small birds.

SpeciesArisaema serratumJapanese Jack-in-the-Pulpit

Essentials

At a Glance

Plant Type

Perennial

Height

24 inches

Width

12 inches

Light

Partial Sun, Shade

Zones

5, 6, 7, 8, 9

Water

Moist

Humidity

High

Lifespan

Perennial

Native To

East Asia

Toxicity

Toxic if ingested

Bloom period

Early spring – Mid-spring

In flower about 2 months of the year

Planting

How to Grow

Tuck seeds into moist soil in early spring
Keep soil consistently moist during growing season
Provide partial shade for optimal growth
Mulch around base to retain moisture
Divide clumps every 3-4 years in early spring
Protect from frost in colder zones

Pro Tip

Plant in shaded areas with well-draining, moist soil for best results.

Keep It Thriving

Care Guide

Do

Water regularly to keep soil moist 🌱
Apply a layer of mulch to conserve moisture
Divide every 3-4 years in early spring
Protect from frost in colder zones

Don't

Avoid dry or overly sunny locations ❌
Do not let soil dry out completely
Avoid heavy, waterlogged soils

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Fertilize
Mulch
Plant

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Shaded woodland gardenMoist border plant

Companion Plants

Hostas Ferns Astilbe Ligularia

Multiply

Propagation Methods

Good to Know

Common Questions

Ulleung Treasure Japanese Cobra Lily questions

What zones can Ulleung Treasure Japanese Cobra Lily grow in?

Ulleung Treasure Japanese Cobra Lily is hardy in USDA Zones 5–9. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Ulleung Treasure Japanese Cobra Lily deer resistant?

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

When does Ulleung Treasure Japanese Cobra Lily bloom?

Ulleung Treasure Japanese Cobra Lily typically blooms in early spring through mid-spring. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Ulleung Treasure Japanese Cobra Lily need full sun?

Ulleung Treasure Japanese Cobra Lily does best in part shade.