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False goat's beard · Astilbe

Why are there white spots on my garden astilbe?

Those white, powdery spots are likely powdery mildew, a common fungal issue for astilbes. Check the leaves for a dusty appearance to confirm this diagnosis.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Look closely at the leaves for a white, dusty texture.
  2. Check if the plant is crowded by other foliage.
  3. Inspect the undersides of leaves for other signs of distress.

Likely causes

  1. Powdery Mildew

    Most likely

    How to tell: White, flour like patches appear on the surface of the leaves and stems.

    What to do: Remove the most affected leaves to improve airflow. Apply a neem oil spray or a fungicide labeled for powdery mildew in the evening.

  2. Poor Air Circulation

    Possible

    How to tell: The plant is crowded by other shrubs or planted in a stagnant, humid corner.

    What to do: Prune back neighboring plants to allow better airflow. Avoid overhead watering that keeps the foliage wet for long periods.

Leaf spots on other plants

Find out what's wrong with your false goat's beard

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

Worry if the mildew covers most of the foliage, as this prevents the plant from photosynthesizing. Minor spots are manageable.

Stopping it coming back

Space your plants properly to ensure good airflow and water at the base rather than over the leaves.

False goat's beard: spots? Check yours with a photo

Every plant is a little different. Take a photo of your false goat's beard 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

Will powdery mildew kill my astilbe?
It rarely kills the plant, but it can weaken it and make it look unsightly. Treat it early to keep the plant healthy.
Should I throw away infected leaves?
Yes, dispose of them in the trash rather than the compost pile to prevent the fungus from spreading.

Guides to these causes

More problems with False goat's beard

Back to the False goat's beard 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.