Weeds must be present to control (Cattails and other emergent vegetation). Best kill when emerged weeds are actively growing Add non-ionic surfactant to enhance uptake of chemical. Non selective kills vegetation that receives treatment to the root. 1 qt makes up to 25 gallons spray solution. Treats up to 10,000 sq ft/1/4 acre of target weeds. Thoroughly cover weeds for optimum kill.