Native to Central America, Catweed is an erect, bushy, leafy, many-stemmed
herb, growing to 2 m tall. It commonly occurs in disturbed areas. Leaves
are opposite, soft, thin, shaped like a triangle or rhombus, with a toothed
edge and conspicuous veins. They are dark green on the upper surface,
lighter underneath, and may be slightly hairy; 4-12cm long, 3-9cm wide.
Flowers profusely in spring and summer, producing dense clusters of white
sticky hairy flowers, 5-8 mm in diameter, at the ends of the branchlets.
Seed production is enormous - 10,000 to 100,000 per year when mature. The
seeds are very small, light, brown to black, with a 4mm 'parachute' of
white hairs, mid to late spring. Germination rates are high.