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Honey fungus · Armillaria

Why is my plant suffering from sudden leaf drop?

Sudden leaf drop in a host plant is a classic symptom of a failing root system caused by Honey fungus. The fungus cuts off the water and nutrient supply to the branches. Check the bark near the ground for signs of the infection.

Check these first

  1. Examine the bark at the soil level for white mycelium.
  2. Check if the plant has been stressed by drought recently.
  3. Look for rhizomorphs, which look like black bootlaces, in the soil.

Likely causes

  1. Advanced root decay

    Most likely

    How to tell: Leaves fall while still green or shortly after yellowing. The plant looks like it is dying from the bottom up.

    What to do: Remove the infected plant and all associated roots. Do not replant susceptible species in that spot for several years.

  2. Environmental stress

    Possible

    How to tell: The plant drops leaves during a drought or heatwave. This weakens the plant and makes it more susceptible to fungal attack.

    What to do: Provide consistent water during dry spells. Mulch around the base to keep the roots cool and moist.

Find out what's wrong with your honey fungus

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

Sudden, heavy leaf drop is a sign of advanced decline. It is almost always too late to reverse the damage once this occurs.

Stopping it coming back

Avoid wounding the roots or trunk during gardening. Keep the area clear of decaying wood where the fungus thrives.

Keep your honey fungus healthy from here

Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked. Identification and a health check are free.

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Questions people ask

Will the leaves grow back?
If the roots are infected by Honey fungus, the plant will not recover. The leaf drop is a sign of permanent damage.
Can I compost the fallen leaves?
It is safer to burn or dispose of the leaves in the trash. Do not put them in your home compost pile.

More problems with Honey fungus

Back to the Honey fungus guide

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