Devil weed (A.K.A Siam weed, bitter bush) is a well-documented pest in Africa, Asia, and Oceana and is considered one of the world’s worst 100 invasive species by the Global Invasive Species Database. It is highly invasive and on the Hawai’i State Noxious Weed List. Devil weed received a high score on the Hawai’i Weed Risk Assessment (HWRA), suggesting it has the potential to be exceedingly invasive in Hawaiʻi.
By understanding the vectors, impacts, and management methods, the community can suppress the spread of devil weed and in turn, reduce the impacts to agriculture and the environment.
Monitor your pastures, farms, and yards for devil weed every 3-6 months. Remove plants and dispose in the trash, NOT GREENWASTE. The average flowering season is December – February. Removing plants before they mature and set seed will significantly diminish the population. Scent detection dogs are trained to detect devil weed and can survey large areas. K9 services are now available.
For identification and management of devil weed Download the informational packet HERE.