Chromolaena odorata (chromolaena) is a thicket-forming perennial shrub up to 3m high.

Chromolaena is a serious invasive weed. It inhibits the growth of other plants through allelopathy, young leaves are toxic to grazing animals and it is a fire risk during die-back following flowering and seeding. It invades open areas including pastures, sugarcane, coconut and other open canopy crop plantations, fallow areas and roadsides.

Seeds are windblown over short distances. They move over greater distances including across borders by adhering to people's clothing, used vehicles, farm machinery and other equipment. 

Native to the Americas and Caribbean, it is present in Guam, Federated States of Micronesia, and Papua New Guinea and was recently found in the Marshall Islands where an eradication programme is being supported by SPC. It prefers well-drained conditions receiving more than 1,000 mm annual rainfall from sea level to 1,000m. 

Any occurrence of this species in Pacific island countries should be reported to the relevant quarantine authorities and / or SPC Plant Protection Service by e-mail: Warea Orapa and Konrad Englberger (FSM-Pohnpei).