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Common toadflax · Linaria vulgaris

Why are there spots on my common toadflax leaves?

Spots on common toadflax are often a sign of fungal issues caused by damp conditions or poor airflow. The most common culprit is powdery mildew, which looks like white dusty patches. Check the undersides of the leaves and the base of the plant for signs of moisture buildup.

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spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Look for white dust on the leaves to identify powdery mildew.
  2. Check if the soil is staying wet for too long between waterings.

Likely causes

  1. Powdery Mildew

    Most likely

    How to tell: White, powdery spots appear on the leaves and stems. These spots can spread and cause the leaves to yellow or curl.

    What to do: Improve air circulation by thinning out nearby plants. You can spray the leaves with a mixture of 1 tablespoon of baking soda in a gallon of water to treat the fungus.

  2. Leaf Spot Disease

    Possible

    How to tell: Dark brown or black spots with yellow halos appear on the foliage. This is often caused by water sitting on the leaves for too long.

    What to do: Remove and destroy the infected leaves to stop the spread. Always water at the base of the plant rather than overhead to keep the leaves dry.

Leaf spots on other plants

Find out what's wrong with your common toadflax

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.

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When to worry

Small spots are manageable, but if the entire plant is covered, it may struggle to photosynthesize and could die back.

Stopping it coming back

Water only at the base of the plant and ensure there is enough space between plants for air to move.

Common toadflax: spots? Check yours with a photo

Every plant is a little different. Take a photo of your common toadflax 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

Is powdery mildew harmful?
It weakens the plant and makes it look unsightly, so it is best to treat it as soon as you see it.
Should I use a fungicide?
You can use a garden fungicide if the infection is severe, but improving airflow is the most important step.

Guides to these causes

More problems with Common toadflax

Back to the Common toadflax guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.