Overview

Eupatorium cannabinum 'Plenum' is a perennial in the genus Eupatorium, part of the Asteraceae family. It typically grows around 1.5 m tall. Eupatorium cannabinum 'Plenum' grows best in full sun, and tolerates most soils. Its UK hardiness is rated H7. Suggested uses include borders, wild gardens and damp areas. It is native to North European Russia, South European Russia, Cyprus, Denmark, Hungary, Morocco, Belgium and Lebanon.

About

A perennial with double flowers, Eupatorium cannabinum 'Plenum' reaches about 1.5 metres and produces its blooms from July to October. It belongs to the Asteraceae family and carries the fuller-flowered form of hemp-agrimony. Plant in moist to wet soils — sandy, loamy or clay — in full sun or partial shade. Fully hardy (H7) in UK gardens and suited to damp borders and wild garden corners.

Wikipedia contributors, CC BY-SA 4.0 — Eupatorium cannabinum

About the genus

Eupatorium is a genus of flowering plants in the family Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennials growing to 0.5–3 m (1.6–9.8 ft) tall. A few are shrubs.

Wikipedia contributors, "Eupatorium", CC BY-SA 4.0 — Eupatorium

In the garden

Eupatorium cannabinum 'Plenum' is a double-flowered form of hemp-agrimony in the Asteraceae, native to parts of Europe, the eastern Mediterranean and North Africa including North and South European Russia, Cyprus, Denmark, Hungary, Morocco, Belgium and Lebanon. It typically grows to around 1.5 metres, forming a substantial perennial clump that carries its flowers above the foliage from July to October. Give 'Plenum' a position in full sun or partial shade on soils that remain moist; it tolerates sandy, loamy and clay textures provided they are not allowed to dry out completely. The cultivar is rated H7 for UK hardiness, meaning it withstands UK winter conditions without special protection. For growers outside the UK, USDA zones 4–8 are the reported range. Use it at the back of a mixed border, beside a pond or in damp wild garden areas where moisture is reliable. Its height and flowering period make it useful for extending interest into late summer and early autumn. Expect the double flowerheads of 'Plenum' to remain prominent from July through October, providing structure in damp patches where many other perennials will fade.

Growing conditions

Best soil and position for Eupatorium

Sunlight

Full sun

Soil type

Sandy, Loamy, Clay

Soil moisture

Moist but well-drained, Wet

Exposure

Full sun, Partial shade

UK hardiness

H7

Plant details

Eupatorium cannabinum 'Plenum' size, habit and characteristics

Plant type

Perennial

Height

1.5 m

Suggested uses

Borders, Wild gardens, Damp areas

Native to

North European Russia, South European Russia, Cyprus, Denmark, Hungary, Morocco, Belgium, Lebanon

Care notes

Pruning and caring for Eupatorium cannabinum 'Plenum'

Cultivation

Prefers moist, fertile soil; tolerates wet conditions; best in full sun or partial shade

Pruning

Cut back after flowering to maintain shape and encourage fresh growth

Propagation

Division in spring or autumn; seed propagation possible but less common for cultivar

Frequently asked questions

More in the Eupatorium genus

• 
  Eupatorium ageratoidesWhite Snakeroot
• 
  Eupatorium cannabinumhemp agrimony
• 
  Eupatorium fistulosum 'Ivory Towers'Hollow Joe-Pye Weed
• 
  Eupatorium purpureumJoe Pye Weed
• Eupatorium mac. 'Red Dwarf'