Maui pamakani

Ageratina adenophora, known as crofton weed or sticky snakeroot, is a perennial herb or subshrub of the daisy family (Asteraceae) native to Mexico and Central America and widely naturalised as an invasive weed in subtropical highlands of Asia, Africa, Australia and Oceania. It typically reaches 1–2 m in height, with erect, much-branched purplish stems clothed in fine, sticky glandular hairs. The opposite leaves are ovate to triangular-rhombic, 4–10 cm long, with coarsely serrate margins, a pointed tip, and a distinctive sticky-pubescent surface. Numerous small white flower heads, each 3–5 mm across and containing only disc florets, are borne in dense flat-topped corymbs at the branch tips from late winter through spring. The fruit is a tiny black achene with a tuft of fine white pappus bristles, enabling efficient wind dispersal. Crofton weed thrives in disturbed ground, pasture margins, and forest edges, often forming dense monospecific thickets that exclude native vegetation.