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Sun spurge · Euphorbia helioscopia

What are these spots on my Sun spurge?

Spots on your Sun spurge are often caused by powdery mildew, which thrives in humid conditions. Check the leaves for a white, dusty coating that wipes off easily.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Look for a white dusty residue on the leaves.
  2. Check if the leaves stay wet after watering.
  3. Ensure there is good airflow around the plant.

Likely causes

  1. Powdery mildew

    Most likely

    How to tell: White, flour like spots appear on the surface of the leaves. The spots may eventually spread to cover the entire leaf.

    What to do: Improve air circulation around the plant by spacing it away from others. You can wipe the leaves with a mixture of water and a drop of mild dish soap.

  2. Fungal leaf spot

    Possible

    How to tell: Dark brown or black spots with yellow halos appear on the leaves. This happens when water sits on the foliage for too long.

    What to do: Water at the base of the plant instead of over the leaves to keep the foliage dry. Remove any heavily infected leaves to stop the spread.

Leaf spots on other plants

Find out what's wrong with your sun spurge

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

If the spots cover more than half of the leaves, the plant will struggle to photosynthesize. Small, isolated spots are easy to manage with better care.

Stopping it coming back

Water only the soil and keep the leaves dry. Ensure the plant has plenty of space for air to move around it.

Sun spurge: spots? Check yours with a photo

Every plant is a little different. Take a photo of your sun spurge 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

Is the white dust harmful to me?
The mildew itself is not toxic, but the sap of the Sun spurge is a skin irritant. Always wash your hands after touching the plant.
Should I use a fungicide?
Usually, you do not need harsh chemicals. Improving airflow and keeping the leaves dry is almost always enough to clear it up.

Guides to these causes

More problems with Sun spurge

Back to the Sun spurge 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.