The DNR does not encourage the destruction of aquatic vegetation. However, the DNR recognizes that aquatic plants may interfere with a homeowner's right to reasonable access to open water and recreation. To balance the needs of conservation and those of recreation, the DNR has developed an Aquatic Plant Management Program. This program, operated under Minnesota Rules, requires permits for controlling, planting, or destroying aquatic plants and other organisms in public waters and public waters wetlands. Because plants provide many benefits to the water environment, requests to destroy vegetation are limited to areas where plants seriously interfere with recreational use.
Two common ways to control aquatic plants:
- Mechanical control means to cut or pull by hand or with equipment such as rakes, cutting blades, hand-operated, or motorized trimmers. Large-scale mechanical control often uses floating, motorized harvesting machines that cut the plants and remove them from the water. The plants are taken to shore for proper disposal. All plants that are mechanically controlled must be removed from the lake. For more information on mechanical control options, contact the Aquatic Plant Management Program.
- Herbicide control means to use plant-killing chemicals that are applied in liquid, granular, or pellet form. The aquatic plants die (sometimes only the stems and leaves) and decompose in the lake. Areas treated with aquatic herbicide are posted with signs to inform lake users of any water use restrictions resulting from the application of the pesticide. Only herbicides labeled for aquatic use are allowed, and any use of an herbicide for aquatic plant control requires a DNR permit. Using an herbicide without a DNR permit is a misdemeanor, and may result in a citation.
Chart with information on specific herbicides. (14 kb).
Whichever method of control you choose, the cost of control depends on the size and type of project. Aquatic plant control is temporary because aquatic plants grow back from root crowns, seeds, and other plant parts. Information on permits, costs, treatment methods, and herbicide distributors, is included at this website or from Aquatic Plant Management Permitting Staff. You can also discuss control methods with an independent contractor.
Aquatic Invasive Plants
Visit the aquatic invasive plant management page for more information.