Botanical name: Ageratina spp. adenophora
Special note: Poisonous to horses and access to the weed for as little as 8 weeks will cause sickness and permanent damage to the animals.
Photos: Adam Burrowes
Originating in Mexico, Crofton Weed is an aggressive erect many-stemmed perennial shrub to 1-3m tall. Distinguished by long upright purplish woody stems covered with short reddish hairs. The long triangular leaves are opposite and have serrated edges and long stems. Roots have a carrot-like smell when cut. Normally occurs in steep well drained land with little or no frosting.
White tubular florets occur as clusters in dense terminal heads, produced in early spring. Brown to black angular 1.5 - 2 mm long with a parachute-like plume at top of white hairs about 4mm long
Seed is spread by water, wind, and dumping. Also in mud carried by humans, animals and machinery.
Impact on bushland
Crofton Weed grows well in sun or shade. It is usually found in damp areas, along creeks or in places where natural drainage has been altered, such as roadsides, along tracks and at outflow points of stormwater drains.
Manual: Crofton Weed is easily hand pulled, particularly if the soil is moist.
See Manual Weed Control Techniques.
Chemical: Please contact your local control authority for advice on chemical control.
Crofton is closely related to Mist Flower (Ageratina riparia), a serious weed in creeklines, and Blue Billy Goat Weed. Both are serious pasture weeds.
Updated: 18 Jul 2016