Can I save leaves that have spots?

You can treat them, but the spots often leave a mark. It is better to remove the worst leaves to stop the spread.

Will this spread to my other plants?

Yes, powdery mildew spores travel easily on the wind. Keep an eye on your other garden plants nearby.

Smooth Hydrangea: spots, causes and fixes

Check these first

Rub the white spots to see if they wipe off like dust.
Check if the plant is crowded by other shrubs.
Inspect the center of the plant for trapped moisture.

Likely causes

Powdery Mildew
Most likely
How to tell: A white, dusty coating appears on the surface of the leaves, eventually causing them to yellow or curl.
What to do: Prune away heavily infected leaves to improve airflow. Spray the remaining foliage with a mixture of 1 tablespoon of baking soda in a gallon of water.
Poor Air Circulation
Possible
How to tell: The plant is crowded by other shrubs or planted against a wall with no breeze.
What to do: Thin out nearby plants to allow air to move through the hydrangea. Ensure you do not water the leaves directly, as wet foliage encourages fungus.

Leaf spots on other plants

Find out what's wrong with your smooth 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.

When to worry

Mildew is common in late summer. It is only a major concern if it covers the entire plant and causes premature leaf drop.

Stopping it coming back

Water at the base of the plant rather than overhead. Give your hydrangea enough room to breathe by spacing it properly from other plants.

Smooth Hydrangea: spots? Check yours with a photo

Every plant is a little different. Take a photo of your smooth 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.

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

Questions people ask

Can I save leaves that have spots?: You can treat them, but the spots often leave a mark. It is better to remove the worst leaves to stop the spread.
Will this spread to my other plants?: Yes, powdery mildew spores travel easily on the wind. Keep an eye on your other garden plants nearby.

Guides to these causes

Powdery Mildew

Why are there white spots on my hydrangea leaves?