The object of this research was to establish a better understanding of the aquatic capabilities of smartweeds. These plan ts are well-known invaders of shallow water, and certain species can cover the entire surface of a reservoir in a period of a few years. The products of the study provide a better basis for understanding our native plants and the processes and capabilities of the amphibious members of the genus for invading aquatic habitats. Such knowledge is essential for planting programs and informed weed control associated with reservoir management programs.