This study focused on assessing the phytoremediation potential of wetland plants toward atrazine in an aquatic environment. Changes in plant biomass and atrazine content were investigated for three plant species: sweet flag, broadleaf cattail, and narrow-leaf cattail. Atrazine removal and shifts in plant biomass were assessed. Two mathematical models were built to describe atrazine toxicity toward the studied plant species and fate of atrazine during long-term phytoremediation. Sweet flag exhibited the highest tolerance toward atrazine as well as the most efficient atrazine removal rate. The average atrazine half-life was significantly reduced from about 400 days to 5 days. The highest studied initial concentration of atrazine (20 mg/l) was reduced by more than 99% after 40 days.