Cogongrass

Cogongrass (Imperata cylindrica) is a perennial rhizomatous grass in the family Poaceae, widely regarded as one of the world's most invasive plant species, ranking among the top ten worst weeds globally due to its aggressive growth, fire adaptations, and competitive suppression of native vegetation. Native to the tropical and subtropical regions of Asia, Africa, and the Mediterranean, cogongrass has established invasive populations across the southeastern United States, parts of Latin America, and various Pacific islands. The grass forms dense, monospecific stands of erect, sword-like leaves with sharp white midribs, growing 60–120 centimetres tall and producing silky white plumes of wind-dispersed seeds. Its extensive underground rhizome network allows it to survive fire, drought, and cultivation disturbance that destroys competing species. Cogongrass dramatically alters fire regimes by producing large volumes of dry biomass that burn intensely and frequently, eliminating fire-sensitive native plants and preventing forest regeneration. Control is extremely challenging, requiring repeated applications of herbicides such as glyphosate and imazapyr combined with prescribed burning. Despite its invasive character outside its native range, cogongrass has traditional uses in Asia, including thatching, erosion control, and folk medicine. IUCN has not formally evaluated its conservation status.