sentences:  One of the potential solutions to the problem are water drawdowns, as the plant is very sensitive to drying out and the plant can die in as short as an hour when removed from water.In addition cold weather has been found to be effective in controlling the plant, though this has practical limitations.When herbicides were applied to the plant, the levels of phosphorus and nitrogen increased but not greatly, suggesting that most of the nutrients remained in the plant biomass and did not reabsorb into the water column.