Impatiens Collapse in Hot, Humid Summers: Stem Rot Management

All impatiens died in Northern Westchester, NY. Owner asks if fungus or bad year.

Stem Rot Diagnosis

Black/brown stems rotting at soil line = fungal stem rot (Rhizoctonia, Pythium). Soft-stemmed impatiens collapse quickly once infected.

Why This Year

Hot, humid weather nationwide favors pathogens. Overcrowding, overhead watering, poor air circulation compound it.

Prevention for Next Season

• Remove all diseased plants and debris.
• Let bed dry thoroughly.
• Space plants for air movement.
• Water at base only—early morning.
• Select shaded sites.

No effective curative spray—sanitation and environment are key.