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Check these first
- Inspect the undersides of the leaves for powdery orange dust.
- Check if the plant is crowded by other foliage.
- Look for signs of standing water that might be stagnant.
Likely causes
Rust Fungus
Most likelyHow to tell: You will see small orange or brown pustules on the leaves. These often appear when the air is humid and airflow is poor.
What to do: Remove and destroy the infected leaves immediately to stop the spread. Improve air circulation around the plant by thinning out dense growth. Avoid overhead watering to keep the foliage dry.
Leaf Spot Disease
PossibleHow to tell: These spots are usually darker, often with a yellow halo around them. They appear as irregular blotches rather than powdery dust.
What to do: Trim away the affected foliage to prevent the fungus from spreading to healthy parts. Ensure the plant is not sitting in stagnant water that has become overly warm. Apply a copper based fungicide if the infection continues to spread.
Find out what's wrong with your marsh foxtail
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 plant, it may struggle to recover. A few spots are manageable with quick pruning.
Stopping it coming back
Keep the area around your marsh foxtail clear of debris and ensure good airflow. Always water at the base of the plant instead of over the leaves.
Marsh foxtail: spots? Check yours with a photo
Every plant is a little different. Take a photo of your marsh foxtail 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 save a leaf with spots?
- It is usually better to remove the leaf entirely. This prevents the fungal spores from spreading to the rest of your plant.
- Will these spots kill my grass?
- If left untreated, severe rust can weaken the plant significantly. With prompt removal of infected parts, your marsh foxtail should bounce back.
Guides to these causes
More problems with marsh foxtail
Back to the marsh foxtail 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.