Should I cut off all the spotted leaves?

Yes, removing infected leaves helps prevent the fungus from spreading to healthy parts of the plant. Dispose of them in the trash rather than the compost pile.

Can I use a fungicide?

You can use a copper based fungicide if the infection is severe. Always follow the label instructions for the correct application rate.

Pontic rhododendron: spots, causes and fixes

Check these first

Inspect the undersides of the leaves for pests.
Check if the spots have a distinct border or halo.
Observe if the spots appear mostly on the leaves getting the most sun.

Likely causes

Leaf Spot Fungus
Most likely
How to tell: You will see circular or irregular brown spots with dark borders on the foliage. These often appear after periods of high humidity or overhead watering.
What to do: Remove and destroy all affected leaves to stop the spread. Improve air circulation around the plant and avoid wetting the leaves when you water.
Sunscald
Possible
How to tell: This is less common for this plant, usually caused by sudden exposure to intense afternoon sun after a period of shade. You will see bleached or scorched patches on the leaves facing the light source.
What to do: Provide a shade cloth or move the plant to a spot with filtered light. Ensure the soil stays moist to help the plant recover from heat stress.

Leaf spots on other plants

Find out what's wrong with your pontic rhododendron

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

Worry if the spots are spreading rapidly across the entire shrub. It is normal to see a few old leaves with minor blemishes as the plant ages.

Stopping it coming back

Keep the foliage dry by watering at the base of the plant only. Space your shrubs properly to allow for good airflow.

Pontic rhododendron: spots? Check yours with a photo

Every plant is a little different. Take a photo of your pontic rhododendron 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

Should I cut off all the spotted leaves?: Yes, removing infected leaves helps prevent the fungus from spreading to healthy parts of the plant. Dispose of them in the trash rather than the compost pile.
Can I use a fungicide?: You can use a copper based fungicide if the infection is severe. Always follow the label instructions for the correct application rate.

Guides to these causes

Leaf Spot

Why are there spots on my Rhododendron leaves?