Invasive aquatic plants are non-native plants that can potentially create recreational nuisances to lakes and reduce native plant diversity. In some instances, when invasive plants become too abundant, they can cause economic or environmental harm. The DNR’s goal of invasive plant management is to minimize harmful effects caused by invasive plants while also protecting the natural resources and their use in the State. Once an invasive species is established in a waterbody, eradication is an unrealistic goal. Plant management is complex, and reductions in invasive plants often require long-term and resource-intensive efforts. Discussing your management proposal(s) with a local Invasive Species Specialist is recommended as a first step.
Management of invasive aquatic plants that involves either mechanical removal of plants or application of herbicides to public waters requires a permit from the DNR. Permits may be issued to property owners, lake organizations and local governments.
Commonly managed aquatic plants are:
New in 2017
To apply for an IAPM permit please use the online Minnesota DNR Permitting and Reporting System (MPARS). If you are using MPARS for the first time, you will need to create an account. Then click on the link "Apply for a New Permit/Authorization" and select "Control invasive aquatic plants (e.g. Eurasian watermilfoil, Curly-leaf pondweed)" as the permit type. If you can't apply online, contact your local Invasive Species Specialist to request a paper application.
The littoral area is the surface area of a body of water where the depth is 15 feet or less and where most aquatic plants will grow. The littoral area is used to calculate the cumulative area in which aquatic plant management may occur. The following permit restrictions are intended to reduce risk of damage to native plants and impacts to water quality. Additional information is available on the value of aquatic plants and water quality.
In some instances, the DNR may allow treatment of more than 15% of the littoral area with herbicides or more than 50% with mechanical removal under a variance and a permit. Consult with the DNR prior to considering this type of treatment.
Delineation surveys are used to map the distribution and density of aquatic invasive plants. They are useful in determining appropriate treatment area and size and in evaluating efficacy post-treatment. Surveys should be conducted on a seasonal basis. If you are considering invasive aquatic plant management, working with local governments, lake consultants or other partners may be helpful in determining the appropriate treatment area. Proposed treatment areas are usually dominated by invasive aquatic plants or areas of high recreational use.
A DNR field inspection is required for all proposed treatment areas prior to issuing a permit. A field inspection may be waived if the proposed treatment areas are delineated by a third party consultant or at the discretion of your local Invasive Species Specialist.
Grant money may be available to support aquatic invasive plant management.
Find your local Invasive Species Specialist.