Description
Eriophorum angustifolium, known as common cottongrass or bog cotton, is a UK native sedge of bogs and boggy moorland. Its small flowers in spring are followed by white, cotton-wool seed heads, which are most noticeable in summer. It is a sedge, not a true grass.
Common cottongrass at a glance
| Botanical name |
Eriophorum angustifolium |
| Common name |
Common cottongrass, bog cotton |
| Plant type |
Evergreen sedge; spreads by rhizomes |
| Height and spread |
About 30 cm tall (up to 50 cm), spreading 1–1.5 m |
| Flowers |
Small and inconspicuous, April to June, followed by white cottony seed heads |
| Position |
Full sun |
| Soil |
Wet, poorly drained, acid soil |
| Pond depth |
0–5 cm of water over the crown |
| Hardiness |
RHS H7 – very hardy (below -20°C) |
| Native to |
UK and Ireland (native wild plant) |
Where to plant common cottongrass
- Acid bog gardens
- The wet edge of a wildlife pond, with up to 5 cm of water over the crown
- A sunny, open spot
What soil does it need?
Wet, acid soil. It may struggle in alkaline or nutrient-rich ponds, so it is best in acid conditions.
Does it spread?
Yes. It spreads by rhizomes and covers ground better than the tufted Eriophorum vaginatum. The RHS gives a spread of 1–1.5 m.
Is it legal to grow?
Yes. It is a native plant and is not on any restricted list. Buy nursery-grown plants: digging up wild plants without the landowner's permission is an offence.
Which size should I buy?
Bare-root plants (7 cm, 9 cm, 1 litre and 3 litre) arrive without a pot or compost and are the most economical way to plant a group. Potted plants (9 cm, 1 litre and 3 litre) arrive growing in our peat-free compost and give a faster display. Packs of 3 come in 7 cm, 9 cm, 1 litre and 3 litre bare-root sizes and cost less per plant. The 2x Pot & Compost option is two plants supplied with pots and compost.
