Robust perennial herb to 2.5 m tall. Stems erect, branched above. Leaves only along stems, broad-lanceolate, to 12 cm long, entire. Capitula many, about 2 cm across; summer. Ray florets white to violet or purple. Pappus of numerous conspicuous scales or bristles, sometimes absent.

SE USA

 

B. asteroides L'Hér. var. latisquama (A. Gray) Cronquist from central USA differs from var. asteroides in having narrower leaves, larger capitula (2.5 cm or more across), blueviolet ray florets and smaller pappus scales [B. latisquama A. Gray]; B. 'Snowbank' grows to 2 m tall and has pure white flowers.

Source: Jeanes, J. (2002). Asteraceae. In: Spencer, R.. 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.