When does it usually flower?

Common cottongrass typically blooms in late spring to early summer. You will see the cottony heads appear shortly after.

Should I prune the old flowers?

You can trim them off once they look messy, but it is not strictly necessary for the health of the plant.

Common cottongrass: not flowering, causes and fixes

Check these first

Measure the amount of direct sun the plant receives.
Check if the plant has been in the same soil for more than two years.
Look for signs of new growth at the base.

Likely causes

Insufficient light
Most likely
How to tell: The plant is growing tall and thin but shows no signs of flower stalks. The leaves look pale green.
What to do: Move the plant to a location that receives at least 6 to 8 hours of direct sunlight daily. If indoors, use a high intensity grow light.
Nutrient deficiency
Possible
How to tell: The plant looks generally weak and fails to develop new growth or flower buds. The soil has not been refreshed in over a year.
What to do: Apply a very weak, balanced liquid fertilizer once in early spring. Do not overfeed, as this plant is adapted to nutrient poor bog conditions.

Other plants that won't flower

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.

When to worry

If the plant is healthy and green but simply not blooming, it may just be too young. It usually takes a full season to establish before flowering.

Stopping it coming back

Ensure the plant gets full sun throughout the growing season and keep the water levels consistent.

Common cottongrass: not flowering? 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.

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Questions people ask

When does it usually flower?: Common cottongrass typically blooms in late spring to early summer. You will see the cottony heads appear shortly after.
Should I prune the old flowers?: You can trim them off once they look messy, but it is not strictly necessary for the health of the plant.

Why is my common cottongrass not producing its cottony heads?