Ageratum Houstonianum

Jun, Jul, Aug

Annuals, Annual, Usually annual or short-lived perennial, erect to decumbent, simple or sparingly branched herb or sub-shrub to 1 m; stem terete, whitish pubescent and with some long, simple hairs.

Annual

Fluffy, aster-like flowers that grow in clusters. Most commonly blue but can be pink or white. Terminal in clustered cymose heads; heads 1/4" diameter; Involucral bracts imbricated in several series. Lavendar, blue to pink, or white, tubular with 5 small lobes; pistils exerted, styles forked.

Fruit is a cypsela which is a type of achene., Achenes 1.2–2 mm long, sub-glabrous, with occasional setae between ribs; pappus 0–3 mm long, of 5 free triangular scales, lacerate, acuminate into a slender awn with scabrid margins, or pappus awnless, scales coroniform, truncate, or occasionally pappus absent.