Description
Eupatorium cannabinum, known as hemp agrimony, is a tall UK native wild flower of damp grassland, marshes, fens and riverbanks. Its reddish stems carry dark green, divided leaves, and from July to September dense, domed heads of tiny pale pink to mauve flowers.
Hemp agrimony at a glance
| Botanical name |
Eupatorium cannabinum |
| Common name |
Hemp agrimony |
| Plant type |
Tall, fast-spreading perennial |
| Height and spread |
About 1–1.5 m tall and wide |
| Flowers |
Pale pink to mauve, in dense domed heads, July to September |
| Position |
Full sun or part shade |
| Soil |
Moist or wet clay or loam; any pH |
| Pond depth |
None – damp ground, not water |
| Hardiness |
RHS H7 – very hardy (below -20°C) |
| Native to |
UK (native wild flower) |
Is hemp agrimony a pond plant?
It is a damp-ground and bog plant, not a water plant. Plant it in moist or wet soil beside a pond or in a bog garden, not in the water. It spreads quickly and self-seeds, so give it room.
Is it good for wildlife?
Yes. It is on the RHS Plants for Pollinators list, and its flowers are very attractive to butterflies such as small tortoiseshell and red admiral, as well as many other insects.
Is it poisonous?
Yes. It contains pyrrolizidine alkaloids, which harm the liver, so it must not be eaten.
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.
