Troubleshooting
Plum 'Stanley' problems — and how to fix them
Plum 'Stanley' (Prunus domestica 'Stanley') 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.
Black knot
A fungal disease common on Stanley in North America causing hard black swellings on stems. Prune out knots well below the swelling in winter and destroy the wood to limit spread.
Brown rot
Fruit rots with soft brown patches and buff spore rings, spreading rapidly in warm, humid weather. Remove infected and mummified fruit and thin for airflow.
Silver leaf
Wounds let in a fungus that silvers the foliage and causes dieback. Prune only in dry summer weather and remove dead wood to limit infection.
Plum curculio
A weevil whose larvae tunnel fruit, causing crescent scars and drop, particularly in eastern North America. Collect dropped fruit and monitor at petal fall to time control.
Prevent plum 'stanley' problems before they start
Most plum 'stanley' issues are care-mismatch, not bad luck. Dial in the basics:
Looking for plum 'stanley' in general rather than its problems? Read the full plum 'stanley' care guide — light, water, soil and feeding.
Plum 'Stanley' problems — FAQ
Why is my plum 'stanley' black knot?
A fungal disease common on Stanley in North America causing hard black swellings on stems. Prune out knots well below the swelling in winter and destroy the wood to limit spread.
Why is my plum 'stanley' brown rot?
Fruit rots with soft brown patches and buff spore rings, spreading rapidly in warm, humid weather. Remove infected and mummified fruit and thin for airflow.
Why is my plum 'stanley' silver leaf?
Wounds let in a fungus that silvers the foliage and causes dieback. Prune only in dry summer weather and remove dead wood to limit infection.
Why is my plum 'stanley' plum curculio?
A weevil whose larvae tunnel fruit, causing crescent scars and drop, particularly in eastern North America. Collect dropped fruit and monitor at petal fall to time control.