Pocket Botanist
Check these first
- Check if the spots are mostly on the lower leaves.
- Look for a white powdery substance on the leaf surface.
- Observe if the spots appear after heavy rain.
Likely causes
Cercospora Leaf Spot
Most likelyHow to tell: These appear as small, circular, dark brown or purple spots on the lower leaves. They often have a lighter center and may cause the leaf to turn yellow and drop.
What to do: Remove and destroy any infected leaves that fall to the ground. Apply a copper-based fungicide every 7 to 14 days during wet spells to protect new growth.
Powdery Mildew
PossibleHow to tell: This looks like a white, dusty coating on the surface of the leaves. It usually happens when nights are cool and days are humid.
What to do: Improve air circulation by thinning out crowded branches. Apply a fungicide labeled for powdery mildew if the infection covers more than a small portion of the plant.
Find out what's wrong with your panicle hydrangea
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
Leaf spots are mostly cosmetic, but severe cases can cause premature leaf drop. If the plant loses most of its foliage, it will struggle to store energy for next year.
Stopping it coming back
Water at the base of the plant rather than overhead to keep the foliage dry. Space your plants properly to ensure good airflow.
Panicle Hydrangea: spots? Check yours with a photo
Every plant is a little different. Take a photo of your panicle hydrangea 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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Or go to pocketbotanist.app/get on your phone
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Questions people ask
- Should I cut off all the spotted leaves?
- You can remove heavily infected leaves to improve appearance and reduce fungal spores. Do not remove more than one third of the plant at once.
- Will my plant recover next year?
- Yes, panicle hydrangeas are resilient. Clean up all fallen debris in the autumn to prevent the fungus from overwintering.
Guides to these causes
More problems with Panicle Hydrangea
- Why are there bugs on my panicle hydrangea?
- Why is my panicle hydrangea drooping?
- Why are my panicle hydrangea leaves turning yellow?
- Why is my panicle hydrangea not blooming?
- Why are my panicle hydrangea leaves getting brown tips?
- Why is my panicle hydrangea dropping leaves?
- Why does my panicle hydrangea have root rot?
- Why is my panicle hydrangea looking leggy?
- Why are my panicle hydrangea leaves curling?
Back to the Panicle Hydrangea 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.