Large shrub or small tree to 5 m tall, more or less hemispherical. Stems erect, densely branched. Leaves elliptical, to 10 cm long, to 4 cm wide, margins sparsely toothed, subsessile. Capitula in clustered corymbs, to 8 mm across; autumn. Florets cream or tinged with pink. Pappus often pinkish. [Eupatorium ligustrinum DC.]
A. altissima (L.) R.M. King & H. Rob. from E North America is a perennial herb or shrub to 2 m tall, with narrow entire upper leaves, capitula in clustered corymbs and white florets. [Eupatorium rugosum hort., Ageratum altissimum L.]
Source: (2002). Asteraceae. In: . Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.