Cobra lily (Arisaema consanguineum) is one of the most architecturally dramatic shade plants available — a tall, slender spathe striped in green and purple rises above a whorl of radiating leaflets, resembling a cobra about to strike. The flowers (technically a spadix within the spathe) are unusual rather than pretty. Followed by attractive clusters of red berries in autumn.
This is a plant for shade gardens and woodland settings where its unusual form can be appreciated up close. All parts are toxic if ingested.
Crown Rot
Lower leaves yellow and wilt; the base of the rosette turns brown and soft, sometimes with white fungal threads at the soil line. Plants collapse in wet conditions.
Remove and destroy affected plants. Improve drainage and avoid overhead watering. Do not mulch directly against the crown. Space plants for airflow and avoid replanting in the same wet spot.
Rust
Orange to brown raised pustules on the undersides of leaves, with yellow spotting on the upper surface. Heavy infections cause leaves to yellow and drop.
Remove and destroy infected leaves. Avoid overhead watering and improve air circulation. Apply a sulfur or copper-based fungicide if it spreads. Clear plant debris in fall.