Crofton Weed

Ageratina adenophora

Alternative Name(s): Eupatorium adenophorum.

Family: Asteraceae.

Form: Herb

Origin: Native to Central America.

Flowers/Seedhead: Flowers: Clusters of white, tubular flowers. The clusters produced in profusion in early spring.

Description: Erect many-stemmed perennial to about 2 m tall. Stems purplish. Roots thick, yellowish, extensive in mature plants. Seed brown to black, angular, 1.5–2 mm long, with a parachute-like plume of white hairs (pappus) about 4 mm long at the top of the seed.

Distinguishing features: Distinguished by some hairs that are sticky, clusters of white flowers, ribs of seeds hairless, triangular to rhombic opposite leaves, and roots with a carrot-like smell when broken.

Dispersal: Seeds carried by water and by strong wind. Transported in hay, machinery, vehicles, clothing and mud.

Confused With: Mistflower Ageratina riparia, which has hairs that are not sticky and seeds with hairs on ribs.