Is this harmful to other plants?

Yes, powdery mildew spores can easily spread to neighboring plants through the air. Isolate the affected plant until it is clear.

Can I wash the spots off?

You can wipe the leaves with a damp cloth, but that will not kill the fungus. You must use a fungicide or baking soda spray.

Bulbous buttercup: spots, causes and fixes

Check these first

Look closely at the underside of the leaves for more spots.
Check if the plant is crowded by other foliage.
Inspect the humidity levels in the immediate area.

Likely causes

Powdery mildew
Most likely
How to tell: White, powdery patches appear on the surface of the leaves and stems.
What to do: Remove the most heavily affected leaves immediately. Spray the remaining foliage with a mixture of one teaspoon of baking soda in a quart of water.
Poor air circulation
Possible
How to tell: The plant is packed tightly against other plants or in a corner with no airflow.
What to do: Space your plants further apart to allow air to move freely around the leaves. If indoors, use a small fan to keep the air moving.

Leaf spots on other plants

Find out what's wrong with your bulbous buttercup

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

Powdery mildew is rarely fatal if caught early, but it can weaken the plant over time. Treat it as soon as you see the first white patch.

Stopping it coming back

Water at the base of the plant to keep the foliage dry, and ensure good airflow around the leaves.

Bulbous buttercup: spots? Check yours with a photo

Every plant is a little different. Take a photo of your bulbous buttercup 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

Is this harmful to other plants?: Yes, powdery mildew spores can easily spread to neighboring plants through the air. Isolate the affected plant until it is clear.
Can I wash the spots off?: You can wipe the leaves with a damp cloth, but that will not kill the fungus. You must use a fungicide or baking soda spray.

Guides to these causes

Powdery Mildew

Why are there white spots on my bulbous buttercup?