Pocket Botanist
Check these first
- Inspect the undersides of the leaves for insects.
- Check the water for signs of decay or stagnant debris.
- Examine the spots to see if they are fuzzy or have a halo.
Likely causes
Fungal leaf spot
PossibleHow to tell: You will see small, dark brown or black circular lesions on the floating leaves. These spots often have a yellow halo around them.
What to do: Remove the affected leaves immediately to prevent the spread of spores. Ensure there is good water circulation around the plant to keep the foliage dry.
Pest damage
PossibleHow to tell: Small holes or irregular patches appear on the leaves where insects have been feeding. Look closely at the undersides of the leaves for small larvae or beetles.
What to do: Manually remove any visible pests by hand. If the infestation is heavy, gently rinse the leaves with water to dislodge them.
Find out what's wrong with your water caltrop
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
Worry if the spots are spreading rapidly to healthy leaves or if the entire rosette begins to rot. It is normal for older leaves to show minor wear as they age.
Stopping it coming back
Keep the water clean and ensure the plant has plenty of space to float without overcrowding.
Keep your water caltrop healthy from here
Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked. Identification and a health check are free.
Questions people ask
- Can I use fungicide on my water caltrop?
- No, you should avoid using chemical fungicides as they can harm the aquatic ecosystem and fish. Stick to physical removal of damaged leaves.
- Are these spots contagious to other plants?
- If the spots are caused by a fungus, it can spread to other floating plants in the same container. Isolate the affected plant until it recovers.
More problems with Water caltrop
Back to the Water caltrop guide
This article was generated with AI from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.