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Witches Broom

Disease

Witches broom is a fungal disease that causes dense, abnormal clusters of twiggy growth to sprout from a single point on a branch. It matters because these growths drain the plant of energy and can eventually lead to the death of the affected branches or the entire tree.

Symptoms by part

Stems

You will see thick, broom like clusters of thin, stunted twigs growing rapidly from a central point, often accompanied by swollen or distorted bark tissue.

Causes

  • High humidity levels that allow fungal spores to thrive.
  • Poor air circulation within the canopy of the tree.
  • Presence of the Crinipellis perniciosa fungus in the local environment.

Could be confused with

  • Mistletoe infestation · Mistletoe is a parasitic plant that grows on branches, whereas witches broom is a structural deformity of the tree's own tissue.
  • Genetic mutation · Genetic mutations often result in uniform growth patterns across the plant, while witches broom creates localized, chaotic, and dense clusters.

Treatment

  1. Prune out all affected broom clusters as soon as they appear, cutting at least 6 to 12 inches into healthy wood below the growth.
  2. Sterilize your pruning tools with a solution of rubbing alcohol between every single cut to prevent moving spores to healthy parts of the tree.
  3. Collect and burn or bury all removed plant material immediately to stop spores from spreading back to the tree.

Without chemicals

  • Pruning to open up the canopy for better airflow.
  • Removing and destroying all infected plant debris from the ground beneath the tree.
  • Improving spacing between trees to reduce humidity.

Preventing it

  • Select and plant resistant varieties if they are available in your region.
  • Keep the area under the tree clear of fallen leaves and twigs to reduce the fungal spore load.
  • Ensure trees are spaced far enough apart to allow wind to dry the foliage quickly after rain.

Season

The warm growing season, especially during periods of frequent rainfall.

Spread risk

High

Severity

High

When to act

Act immediately upon spotting the first broom cluster to prevent the fungus from spreading to the rest of the tree. If the infection covers more than half of the tree, it is best to remove the entire plant to protect nearby healthy trees.

Think it's Witches Broom?

This guide covers the general picture. Pocket Botanist looks at your actual plant from a photo and tells you what's really going on, how serious it is, and what to try first. Identification and a health check are free.

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Questions people ask

Can I compost the infected branches I prune off?
No, you should never compost infected material because the fungal spores can survive the composting process and spread to other parts of your garden.
Will my tree recover if I just leave the brooms alone?
No, the brooms will continue to grow and sap the tree of nutrients, eventually weakening it to the point where it may stop producing fruit or die entirely.

Plants it affects

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This guide was generated with AI and is general information, not horticultural advice. Read about how we build these guides.