Arisaema speciosum

Arisaema speciosum is one of those plants that makes people stop and stare. Often called Cobra Lily, it produces a dramatic, hooded “flower” (a spathe) with a slender central spike (spadix), giving it that exotic, sculptural look that’s perfect for shady gardens. The foliage is just as striking—handsome, divided leaves that add a lush, woodland feel from spring through summer.

It’s ideal for shaded borders, woodland planting, and pots in a sheltered spot, especially where the soil stays reliably moist but never waterlogged. Once settled, Arisaema speciosum is a real conversation piece that returns each year with bigger presence and even more character.

Planting Instructions

When to Plant:

Plant in spring while dormant or just as growth begins. You can also plant in early autumn in milder areas, as long as the soil is not waterlogged.

Where to Plant:
Choose a sheltered position in partial shade to full shade with moist, humus-rich, well-drained soil. Arisaema speciosum is ideal for woodland gardens, shady borders, under shrubs and containers. Avoid very dry spots and heavy winter-wet ground.

How to Plant:

• Depth: Plant the tuber/corm about 10–15 cm (4–6 inches) deep.
• Spacing: Space 30–45 cm (12–18 inches) apart, allowing room for the plant to mature.
• Soil Prep: Mix in plenty of leaf mould or well-rotted compost. In heavy soils, add grit to improve drainage.

Watering:
Water well after planting and keep the soil evenly moist during the growing season. Reduce watering once the foliage dies back. In pots, never allow compost to dry out completely in spring and early summer.

Aftercare Tips:

• Mulch annually with leaf mould or compost to keep roots cool and moist.
• Allow foliage to die back naturally—this feeds the tuber for next year.
• In colder areas, protect the crown in winter with a dry mulch, especially in heavy soil.
• If growing in a container, move the pot to a sheltered spot in winter to keep it from sitting wet and frozen.

Top Tip:
Arisaema speciosum loves a woodland-style planting partner—try ferns, hostas, epimediums and spring bulbs. Think “cool roots, moist soil, filtered light” and it will be very happy.

Plant Details

Flowering Period:

May - June (sometimes into July, depending on season)

Height:
18–36" (45–90cm)

Position:
Partial shade / full shade

Hardy Perennial
(Performs best with winter protection in colder, wetter gardens)