Species that are considered high risk have a well-documented history of invasiveness in at least one location globally, and a high or medium climate match to the contiguous United States.
Hygrophila polysperma is native to Southeast Asia. The species has spread for use as an aquarium plant. This plant is well established in Florida and parts of Texas. H. polysperma is declared a noxious weed in the United States. The history of invasiveness for H. polysperma is high. The plant has negative impacts on water control infrastructure, property value, and native plant communities. Climate matching indicated the contiguous United States has a high climate match with already established H. polysperma populations in some states. The climate match indicates that there may be areas with suitable climate outside of currently established populations. The certainty of assessment is medium. The overall risk assessment category is high.