Cooperative Extension: Garden and Yard

I’m going to recommend that you contact the Board of Pesticide Control directly, as they are the regulatory agency that oversees herbicide use in Maine waters and would be the group you’d have to get permission from to spray. The non-chemical approach is mechanical removal (i.e., hand pulling, dredging, or using specialized underwater cutting tools), which can be quite labor-intensive depending on your situation, or the introduction of species that will feed on the cattails.