Will the rust kill my plant?

Usually no, but it weakens the plant significantly. It is best to remove infected parts early.

Should I use a fungicide?

It is rarely necessary for this plant. Good hygiene and airflow are almost always enough.

Great Willowherb: spots, causes and fixes

Check these first

Inspect the undersides of the leaves for orange or brown bumps.
Check if the plant is crowded by other nearby plants.
Look for signs of standing water on the foliage.

Likely causes

Rust Fungus
Most likely
How to tell: You will see small orange or brown bumps on the undersides of the leaves. These spots might eventually spread to the stems.
What to do: Remove and destroy all affected leaves immediately to stop the spread. Improve air circulation around the plant by thinning out dense foliage. Avoid overhead watering to keep the leaves dry.
Fungal Leaf Spot
Possible
How to tell: These spots are usually darker, often brown or black, and may have a yellow halo around them. They appear after periods of heavy rain or high humidity.
What to do: Prune away the damaged leaves to reduce the fungal load. Ensure the plant is not crowded by other vegetation. Keep the base of the plant clear of fallen debris.

Leaf spots on other plants

Find out what's wrong with your great willowherb

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 cover more than half the leaf surface or if the plant stops growing. A few spots are normal in a wet summer.

Stopping it coming back

Water at the base of the plant rather than over the leaves, and ensure plenty of space between plants for airflow.

Great Willowherb: spots? Check yours with a photo

Every plant is a little different. Take a photo of your great willowherb 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.

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Questions people ask

Will the rust kill my plant?: Usually no, but it weakens the plant significantly. It is best to remove infected parts early.
Should I use a fungicide?: It is rarely necessary for this plant. Good hygiene and airflow are almost always enough.

Why does my Great Willowherb have orange spots on its leaves?

Check these first

Likely causes

Rust Fungus

Fungal Leaf Spot

Find out what's wrong with your great willowherb

When to worry

Stopping it coming back

Great Willowherb: spots? Check yours with a photo

Questions people ask

Guides to these causes

More problems with Great Willowherb