Chokecherry Black Knot: Hard Charcoal-Like Branch Growths

Confirming Black Knot Disease

Wide, thick, hard black growths on chokecherry branches, with narrowing at the trunk, are classic black knot (Apiosporina morbosa)—a fungal disease of Prunus species. The "charcoal" description is perfect.

Management Program

1. Prune out all galls 6–8 inches below visible swelling (winter best).
2. Sterilize tools between cuts (10% bleach/alcohol).
3. Destroy prunings (burn/bag)—spores spread from debris.
4. Fungicide prevention: Apply labeled fungicide (search "black knot fungicide") at bud break and petal fall.

Long-Term Outlook

Black knot is chronic but manageable. Annual pruning + preventive sprays keep trees productive. Your prompt removal of affected branches was the right first step.