Cold Damage on Potted Palms in Maryland: Assessment and Care

Palms in Maryland (Zone 6/7) After 40°F Nights: Damage Control

Potted palms moved outdoors in early April, hit by 40°F nights, now showing brown spots and frond death: cold-induced fungal issues and possible root rot.

What Happened

• Palms are tropical; 40°F causes chilling injury
• Cold + damp = ideal for fungal leaf spots (Helminthosporium, etc.)
• Root rot if pots stayed wet in cold (roots inactive, water not used)

Immediate Actions

1. Copper fungicide spray on all foliage (prevents spread)
2. Move to protected location (garage, sunroom) until nights >55°F
3. Reduce watering drastically—only when soil dry 2–3" down
4. Remove fully brown fronds (won't recover)

Prognosis

• Spotted fronds: May recover if new growth healthy
• Fully brown fronds + soft trunk base: Root rot = likely dead
• Firm trunk, green spear: Good chance

Long-Term Maryland Strategy

Palms in ground: not viable. Pots: outdoors May–Sept only. Winter indoors (bright light, 60°F+). Species: Lady palm, Kentia, Parlor palm tolerate lower light/cool better.