Troubleshooting
Cowslip problems — and how to fix them
Cowslip (Primula veris) 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.
Vine weevil
Grubs eat roots from late summer into autumn, causing sudden wilting and plant collapse; apply a nematode drench (Steinernema kraussei) in late August to September when soil is above 5 °C.
Botrytis (grey mould)
Grey fuzzy growth appears on crowns and flower stems in cool, damp conditions; improve air circulation, remove dead leaves promptly, and avoid overhead watering.
Aphids
Cowslip aphid (Aphis primulae) colonies distort young leaves and flower stems in spring; remove by hand or apply a soft-soap spray; avoid systemic insecticides on this pollinator-important plant.
Prevent cowslip problems before they start
Most cowslip issues are care-mismatch, not bad luck. Dial in the basics:
Cowslip problems — FAQ
Why is my cowslip vine weevil?
Grubs eat roots from late summer into autumn, causing sudden wilting and plant collapse; apply a nematode drench (Steinernema kraussei) in late August to September when soil is above 5 °C.
Why is my cowslip botrytis (grey mould)?
Grey fuzzy growth appears on crowns and flower stems in cool, damp conditions; improve air circulation, remove dead leaves promptly, and avoid overhead watering.
Why is my cowslip aphids?
Cowslip aphid (Aphis primulae) colonies distort young leaves and flower stems in spring; remove by hand or apply a soft-soap spray; avoid systemic insecticides on this pollinator-important plant.