Fishtail Palm Brown Spots After Cold Nights? Fungal Fix and Nutritional Boost

Your young fishtail palm (Caryota) in Seminole, FL, has circular brown spots on new leaflets after four sub-40°F nights. You've done everything right: good soil, careful watering, frost protection, timely fertilizer. The spots are likely fungal—cold + moisture = perfect pathogen conditions.

Two-Pronged Treatment

1. Copper fungicide spray on all fronds, top and bottom, every 2 weeks until spots stop spreading.
2. Palm nutritional spray (Southern Ag or similar concentrate) applied early morning when dew opens stomata. Alternate with copper weekly.

Why Morning Dew Matters

Stomata (leaf pores) open at dawn. Spraying then lets nutrients/fungicide enter directly—far more effective than root feeding for acute issues.

Outlook

Spotted fronds won't heal, but new growth should emerge clean. First winter is the gauntlet; once established, fishtails toughen up. Your robellini, cat, and queen palms handle cold better—different species, different hardiness.