Can I spray the leaves with water to clean them?

No, wetting the leaves can actually encourage fungal growth. Keep the foliage dry and focus on soil health.

Are these spots contagious to other plants?

Most oak specific fungi will not spread to your garden flowers or shrubs. They are generally host specific.

What are these spots on my Bur oak leaves? Causes and fixes

Check these first

Examine the underside of the leaves for fungal growth.
Check if the spots are concentrated near the leaf veins.
Look for similar spots on neighboring oak trees.

Likely causes

Bur Oak Blight
Most likely
How to tell: These spots appear as dark, scorched areas that often follow the veins of the leaf. They start small and grow until they cover large sections of the leaf blade.
What to do: Remove and destroy all fallen leaves in the autumn to stop the fungus from overwintering. If the infection is severe, consult an arborist about fungicide injections.
Anthracnose
Possible
How to tell: Small, irregular brown or black spots appear on the leaves, often accompanied by leaf curling. This usually happens during a cool, wet spring.
What to do: Prune out any dead or damaged twigs to improve air circulation. Rake up and discard all fallen leaves to prevent the fungus from spreading next season.

Leaf spots on other plants

Find out what's wrong with your bur oak

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.

When to worry

If the spots cover more than half of the leaf surface or cause the tree to lose its leaves by July, it is a serious issue. A few scattered spots are common and rarely threaten the tree.

Stopping it coming back

Keep the area around the base of the tree clean and ensure the canopy has good airflow.

Bur oak: spots? Check yours with a photo

Every plant is a little different. Take a photo of your bur oak 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.

Get the app · Or check it from a photo now, free

Questions people ask

Can I spray the leaves with water to clean them?: No, wetting the leaves can actually encourage fungal growth. Keep the foliage dry and focus on soil health.
Are these spots contagious to other plants?: Most oak specific fungi will not spread to your garden flowers or shrubs. They are generally host specific.

Guides to these causes

Anthracnose

What are these spots on my Bur oak leaves?

Check these first

Not sure what's wrong with your bur oak?