Pocket Botanist
Check these first
- Inspect the leaves for slimy trails.
- Check the soil surface at night for pests.
- Examine the spots to see if they are holes or discoloration.
Likely causes
Slugs and snails
PossibleHow to tell: You will see irregular holes or chewed edges on the foliage. Look for slimy trails left behind on the leaves or the soil surface.
What to do: Handpick the pests at night when they are active. You can also set out shallow dishes of beer or use iron phosphate bait around the base of the plants.
Fungal leaf spot
PossibleHow to tell: Small brown or black circles appear on the blades, sometimes with a yellow halo. This usually occurs when the foliage stays wet for too long.
What to do: Remove the affected leaves to stop the spread. Water only at the base of the plant to keep the foliage dry.
Find out what's wrong with your black mondo grass
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 damage spreads quickly to new growth. A few small holes from a stray slug are usually not a major threat to the plant.
Stopping it coming back
Keep the area around your grass clear of debris where slugs like to hide. Water early in the morning so the leaves dry off quickly.
Black Mondo Grass: spots? Check yours with a photo
Every plant is a little different. Take a photo of your black mondo grass 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
- Will the spots go away?
- No, the damaged tissue will not heal. You can trim off the worst leaves to keep the plant looking tidy.
- Are these spots a sign of a disease?
- Usually, spots on this plant are caused by pests rather than serious disease. Keep the area clean and dry to prevent issues.
Guides to these causes
More problems with Black Mondo Grass
Back to the Black Mondo Grass 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.