Pocket Botanist
Check these first
- Look closely at the undersides of the leaves for orange dust.
- Check if the plant is crowded by other vegetation.
- Ensure the plant is not sitting in stagnant, humid air.
Likely causes
Mint Rust
Most likelyHow to tell: Small, bright orange, powdery pustules appear on the undersides of the leaves. The leaves may eventually wither and fall off.
What to do: Remove and destroy all infected leaves immediately to stop the spread. Improve air circulation around the plant by thinning out dense growth.
Leaf Spot Disease
PossibleHow to tell: Dark brown or black spots with yellow halos appear on the leaves during periods of high humidity.
What to do: Avoid overhead watering to keep the leaves dry. Remove any damaged foliage and ensure the plant has plenty of space for air to move.
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
If the spots cover more than half of the leaves, the plant is severely stressed. Minor spotting is manageable with pruning.
Stopping it coming back
Space your plants out to allow for good airflow and avoid getting water on the leaves when you refill the container.
Water Mint: spots? 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.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
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Questions people ask
- Is mint rust contagious to other plants?
- Yes, it can spread to other mint family members nearby. Keep infected plants isolated.
- Can I use a fungicide?
- You can, but it is often better to prune the infected parts and improve the environment first.
Guides to these causes
More problems with Water Mint
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.