Alligator weed is an emersed plant. It can grow in a variety of habitats, including dry land, but is usually found in water. It may form sprawling mats over the water or along shorelines.
Alligator weed stems are long, branched, and hollow. Leaves are simple, elliptic, and have smooth margins. Leaves are opposite. The whitish papery flowers grow on stalks. Alligator weed flowers during the warm months.