Troubleshooting
American black currant problems — and how to fix them
American black currant (Ribes americanum) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
White pine blister rust (Cronartium ribicola)
Ribes spp. serve as the alternate host; orange pustules appear on leaf undersides. Planting is restricted or regulated within certain distances of white pine plantations in many US states. Check local regulations before planting.
Currant aphids
Red or green blistering on upper leaf surfaces caused by Cryptomyzus or Aphis species. Rarely fatal but can reduce vigour. Treat with insecticidal soap spray targeting the undersides of leaves early in spring.
Powdery mildew
White powdery coating on young leaves in warm, dry spells. More resistant than European black currant but not immune. Improve air circulation, avoid overhead watering, and apply sulphur-based spray if needed.
Prevent american black currant problems before they start
Most american black currant issues are care-mismatch, not bad luck. Dial in the basics:
Looking for american black currant in general rather than its problems? Read the full american black currant care guide — light, water, soil and feeding.
American black currant problems — FAQ
Why is my american black currant white pine blister rust (cronartium ribicola)?
Ribes spp. serve as the alternate host; orange pustules appear on leaf undersides. Planting is restricted or regulated within certain distances of white pine plantations in many US states. Check local regulations before planting.
Why is my american black currant currant aphids?
Red or green blistering on upper leaf surfaces caused by Cryptomyzus or Aphis species. Rarely fatal but can reduce vigour. Treat with insecticidal soap spray targeting the undersides of leaves early in spring.
Why is my american black currant powdery mildew?
White powdery coating on young leaves in warm, dry spells. More resistant than European black currant but not immune. Improve air circulation, avoid overhead watering, and apply sulphur-based spray if needed.