Pocket Botanist
Check these first
- Look for a white dusty substance on the leaves.
- Check if the spots are brown or black with a yellow ring.
- See if the plant is crowded by other foliage.
Likely causes
Powdery Mildew
Most likelyHow to tell: White, powdery patches appear on the leaves and stems.
What to do: Remove the most heavily infected leaves to stop the spread. Improve air circulation around the plant and avoid overhead watering.
Fungal Leaf Spot
PossibleHow to tell: Dark or brown spots with yellow halos appear on the foliage.
What to do: Keep the leaves dry when watering. Clean up any fallen debris around the base of the plant.
When to worry
If the spots cover most of the leaf surface and cause premature yellowing, the plant is struggling. Small, isolated spots are usually just a minor cosmetic issue.
Stopping it coming back
Water at the base of the plant instead of over the leaves to keep them dry.
Not sure which one it is? Photograph your american burnweed.
This page lists the usual causes. Pocket Botanist looks at your actual leaf and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
Questions people ask
- Is powdery mildew contagious?
- Yes, it spreads easily through the air to nearby plants.
- Should I throw the plant away?
- Not necessarily, as you can often manage it by removing affected leaves and improving airflow.
More problems with American burnweed
Back to the American burnweed 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.