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Water Mint · Mentha aquatica

What are these spots on my Water Mint leaves?

This symptom is less common for this plant, but it can be affected by Mint Rust in damp conditions. Check the undersides of your leaves for small orange pustules.

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pests on a plant
Photo: Jules Verne Times Two, CC BY-SA 4.0

Check these first

  1. Inspect the undersides of the leaves for orange spots.
  2. Look for tiny insects on the new growth tips.
  3. Check for sticky residue on the foliage.

Likely causes

  1. Mint Rust

    Most likely

    How to tell: Small, bright orange or brown powdery pustules appear on the undersides of the leaves. The leaves may eventually yellow and drop.

    What to do: Remove and destroy all infected leaves immediately to stop the spread. Improve air circulation around the plant and avoid getting water on the foliage when watering.

  2. Aphids

    Possible

    How to tell: Tiny green or black insects cluster on the new growth and undersides of leaves. You might see sticky residue on the leaves.

    What to do: Spray the plant with a gentle stream of water to knock the aphids off. If they persist, use an insecticidal soap specifically labeled for edible herbs.

Pests on other plants

Find out what's wrong with your water mint

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

Mint Rust can spread quickly and ruin the harvest, so treat it as soon as you see it. Small numbers of aphids are manageable but should be addressed before they multiply.

Stopping it coming back

Provide good airflow and keep the foliage dry to prevent fungal issues like rust. Inspect your plants weekly for any signs of pests.

Water Mint: pests? Check yours with a photo

Every plant is a little different. Take a photo of your water mint 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

Can I eat the leaves if it has rust?
It is best to avoid eating leaves that show signs of rust. If the infection is widespread, discard the entire plant to protect others.
How do I stop rust from coming back?
Keep the leaves dry and ensure there is plenty of space between plants for air to move. Avoid overcrowding your containers.

Guides to these causes

More problems with Water Mint

Back to the Water Mint 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.