Hemp-agrimony
Eupatorium cannabinum
Hemp-agrimony is a perennial herbaceous plant that reaches heights between 50 and 150 centimeters. It is characterized by its opposite, usually palmately three- to five-lobed leaves and dense, corymbose inflorescences. The numerous small flower heads are mostly light pink to purple and appear from July to September.
Details
Habitat function
Serves as cover for small mammals and amphibians near banks and as an oviposition site for insects.
Nutrient uptake
High uptake of nitrogen and phosphate from the riparian substrate.
Food source for
Nectar source for butterflies (e.g., Jersey Tiger, Red Admiral), hoverflies, and bees.
Human use
Formerly used as a medicinal plant (immunostimulant, diuretic); today rarely used medically due to hepatotoxic pyrrolizidine alkaloids.
Ecology
Ecological role
Important nectar plant for numerous insect species and pioneer plant in moist clear-cuts.
Natural predators
Various insect larvae (leaf miners), ungulates (occasional browsing).
Competitor species
Other tall herbs of moist habitats such as Meadowsweet or Common Nettle.
Ecosystem service
Biodiversity support by providing food for pollinators; bank stabilization.
Threats
Drainage of wetlands and intensive bank management.
Scientific profile
Profile
Reproduction
Generative via wind-dispersed achenes (pappus present) and vegetative through rhizome runners.
Protection & threats
Main threats
Drainage of wetlands, intensive riverbank engineering, excessive mowing of riparian fringes, and invasive neophytes (e.g., Impatiens glandulifera).