Pocket Botanist
Check these first
- Observe how much light the plant gets daily.
- Check if nearby plants are shading it out.
- Look for signs of stretching in the new growth.
Likely causes
Insufficient light
PossibleHow to tell: The blades grow long, thin, and pale instead of short and dark. The plant loses its compact, clumping habit.
What to do: Move the plant to a spot with more bright indirect light. It thrives in partial shade to full sun.
Crowding
PossibleHow to tell: The grass looks stretched as it competes with nearby plants for space. The center of the clump may look thin.
What to do: Divide the clump in spring to give the plant more room to grow. This will help it maintain a dense and healthy appearance.
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.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
When to worry
Legginess is mostly a cosmetic issue, but it can make the plant weaker over time. It is normal for the plant to grow slowly, but it should remain compact.
Stopping it coming back
Provide adequate light and divide the clumps every few years to keep them vigorous. This keeps the growth tight and healthy.
Black Mondo Grass: leggy growth? 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.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
Get the app · Or check it from a photo now, free
Questions people ask
- Will trimming help it grow back thicker?
- Trimming the tips can make it look neater, but it won't fix the underlying cause. You must improve the light to get thicker growth.
- How much light does it really need?
- It prefers bright indirect light but can handle partial shade to full sun. If it is in deep shade, it will likely stretch out.
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.