Over the past several years, managers across the basin have taken advantage of high Great Lakes water levels to successfully control Phragmites by cutting stems under water (‘cut-to-drown’ method). However, several questions remain to determine if these management actions are effective across a wide variety of conditions in the Great Lakes. USGS and USFWS are addressing these management uncertainties through a series of controlled experiments and large-scale field studies. Our findings will inform management decisions as Great Lakes water level fluctuations become more frequent, and managers continue to seek additional control methods for Phragmites.