Ageratina riparia

Ageratina riparia, commonly known as mistflower, is a species of flowering plant in the family Asteraceae, native to Mexico. The species is widely adventive and has spread to Cuba, Jamaica, and other parts of the Caribbean. It has also been introduced as an ornamental plant and naturalized in a variety of regions, including parts of Hawaii, South Africa, Southeast Asia, Macaronesia, Oceania, Peru, and the Indian subcontinent. In tropical climates, A. riparia is highly invasive and a variety of control methods have been developed to reduce its spread....read more on Wikipedia.