Parthenium hysterophorus is an annual herb that aggressively colonises disturbed sites. Native to southern United States, Mexico and Central and South America, it has been accidentally introduced into several countries and has become a serious agricultural and rangeland weed in parts of Australia, Asia, Africa and the Pacific Islands.
It grows on any type of soil and in a wide range of habitats. It affects the production of crops, animals, human and animal health, and biodiversity.
Several characteristics, such as wide adaptability, photo- and thermo-insensitivity, drought tolerance, strong competition and allelopathy, high seed production ability, longevity of seeds in soil seed banks, and small and light seeds that are capable of long distance travel via wind, water, birds, vehicles, farm machinery and other animal traffic, contribute to its rapid introduction world-wide, cutting across national boundaries and climate barriers.