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Check these first
- Move the plant to a location with more direct sunlight.
- Rotate the pot every few days to ensure even light exposure.
- Check if the plant is crowded by other nearby plants.
Likely causes
Lack of direct sun
PossibleHow to tell: The stems become long, thin, and weak as they stretch toward the nearest light source. The plant will look sparse rather than dense and bushy.
What to do: Place the plant in a spot with full, unobstructed sun. If you are growing it indoors, you may need a high intensity grow light to mimic full sun conditions.
Overcrowding
PossibleHow to tell: This is less common for this plant, but can occur if too many plants are competing for the same light in a small container. The stems grow tall and thin because they are shading each other.
What to do: Divide the plant into smaller clumps and repot them into separate containers. Give each plant enough space to receive light on all sides.
Find out what's wrong with your common cottongrass
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 stems are so weak they cannot support themselves, the plant is severely light starved. It is normal for the plant to grow tall during the peak of the growing season.
Stopping it coming back
Keep the plant in full sun and ensure it has enough space to grow without being shaded by other plants.
Common cottongrass: leggy growth? Check yours with a photo
Every plant is a little different. Take a photo of your common cottongrass 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
- Can I prune my leggy cottongrass?
- Yes, you can trim back the long, leggy stems to encourage a more compact shape. Always use clean, sharp shears to make your cuts.
- How much light is full sun for this plant?
- Cottongrass needs at least 6 to 8 hours of direct, unfiltered sunlight every day. Anything less will likely result in weak, leggy growth.
More problems with Common cottongrass
Back to the Common cottongrass 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.