Can I wash the spots off?

You can gently wipe them, but the fungus is systemic and will return unless you treat the environment. Improving airflow is the best long term solution.

Is this harmful to my other plants?

Yes, powdery mildew spores travel easily through the air. Isolate the affected plant immediately to protect your collection.

Common centaury: spots, causes and fixes

Check these first

Look for a dusty white coating on the leaves.
Check if the plant is crowded by other pots.
Assess the humidity levels in your growing area.

Likely causes

Powdery mildew
Most likely
How to tell: White, flour like patches appear on the surface of the leaves and stems.
What to do: Remove the most heavily affected leaves to stop the spread. 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 crowded by other plants or kept in a stagnant, humid corner.
What to do: Space your plants further apart to allow air to move freely between them. If indoors, place a small fan nearby to keep the air moving.

Leaf spots on other plants

Find out what's wrong with your common centaury

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 foliage, the plant will struggle to photosynthesize and may decline rapidly.

Stopping it coming back

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

Common centaury: spots? Check yours with a photo

Every plant is a little different. Take a photo of your common centaury 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 wash the spots off?: You can gently wipe them, but the fungus is systemic and will return unless you treat the environment. Improving airflow is the best long term solution.
Is this harmful to my other plants?: Yes, powdery mildew spores travel easily through the air. Isolate the affected plant immediately to protect your collection.

Guides to these causes

Powdery Mildew

Why are there white spots on my common centaury?

Check these first

Not sure what's wrong with your common centaury?