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Chokecherry · Prunus virginiana

What are these black, warty growths on my Chokecherry?

Those hard, black lumps on your branches are likely a fungal disease called Black Knot. It is a common issue for Prunus species that needs your immediate attention. Check the stems for swelling or rough, dark growths.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Examine the branches for hard, black, warty growths.
  2. Check if the growths are encircling the stems.
  3. Look for small holes in the leaves.

Likely causes

  1. Black Knot Fungus

    Most likely

    How to tell: You will see hard, black, crusty galls that look like burnt charcoal on the branches. These growths continue to expand and circle the branch over time.

    What to do: Prune out the infected branches at least 4 to 8 inches below the visible knot. Sterilize your pruning shears with rubbing alcohol between every single cut to prevent spreading the spores.

  2. Shot Hole Fungus

    Possible

    How to tell: This causes small, circular spots on the leaves that eventually fall out, leaving holes that look like buckshot. It is mostly a cosmetic issue.

    What to do: Rake up and destroy all fallen leaves around the base of the tree in autumn. Avoid overhead watering to keep the foliage as dry as possible.

Leaf spots on other plants

Find out what's wrong with your chokecherry

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

Black Knot is serious if it reaches the main trunk or if the tree is heavily infested. If the knot encircles the main stem, the tree may need to be removed.

Stopping it coming back

Prune your Chokecherry in late winter to improve airflow through the canopy. Always buy disease-free nursery stock to avoid introducing the fungus.

Chokecherry: spots? Check yours with a photo

Every plant is a little different. Take a photo of your chokecherry and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Can I just scrape the black knots off?
No, the fungus grows deep inside the wood. You must prune the entire infected branch off to stop the spread.
Is Black Knot contagious to other trees?
Yes, it spreads via spores in the wind during wet spring weather. Keep a close eye on any other Prunus trees in your yard.

More problems with Chokecherry

Back to the Chokecherry guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.