What's Working for Conservation
Non-native Phragmites Control
2025 Information
Partnerships, EDDMaps and Imazapyr have been critical in controlling non-native Phragmites. Anoka County started detecting non-native
phragmites following Julia Bohnen’s presentation about invasive phragmites at the Minnesota Aquatic Invasive Species Research Center (MAISRC) Showcase. During a routine AIS Early Detection survey on Ham Lake in June 2018, Coon Creek Watershed District staff observed the first known infestation of invasive phragmites within the County. Julia, MAISRC staff, verified the ID and funds from Coon Creek Watershed District and the Anoka Conservation District’s BWSR’s Cooperative Weed Management were used to acquire DNR permits and conduct a fall herbicide treatment and winter mowing. Monitoring occurred the following year and there were no signs of phragmites; the treatment was successful. The search for non-native phragmites continued using University of MN’s easy to use Guide to Identifying Native and Non-native Phragmites australis (funded by LCCMR). An additional 14 non-native phragmites populations were found in Anoka County and recorded in EDDMap, a web-based mapping system for documenting invasive species and pest distribution. Due to the success of the treatment on Ham Lake, Anoka County Parks AIS program provided funds to conduct treatment at the new sites in 2019. Partnerships continued to grow throughout the Metro to control non-native phragmites. Staff throughout the Metro, MAISRC and DNR reviewed invasive phragmites distribution on EDDMaps and requested treatment funds from the MN Department of Agriculture (MDA). EDDMaps created a system for identifying the extent of the problem and an efficient means to send a RFQ to contractors. The location, area, reporter, verifier, cover, abundance and phenology are recorded in the on-line EDDMaps report. Creating a RFQ and maps for a contractor would have been a much more significant undertaking without EDDMaps. PLM Lake and Land Management Corp conducted herbicide treatment at 68 sites (totaling 7.3 acres) in Anoka, Isanti, Carver, Ramsey and Washington County in 2020 funded by the MN Department of Agriculture Noxious Weed and Invasive Plant Grant. Hennepin County also conducted treatment with Hennepin County funds. Local staff monitored sites and found successful treatment at most sites. Non-native phragmites was treated in September with either Habitat at a rate of 0.75 gallons acre or Polaris at a rate of 0.5 gallons per acre. Imazyapr is the active ingredient for both Habitat (28% Imazapyr) and Polaris (53% Imazapyr). A high percentage of non-native phragmites was killed in the first round of treatment such that follow up treatment was only needed on small areas at some sites. Winter mowing occurred at a few sites that had dense stands of phragmites. Mowing cleared away the standing dead biomass so that follow up treatment would be more effective. Local staff, MN DOT and MAISRC staff continued to search and report non-native phragmites on EDDMap during the 2021 growing season. Treatment occurred in September through early October on more than 100 sites throughout the state by multiple Contractors, local and MN DOT staff. Imazapyr has proven to be an effective treatment, however, it does persist in the soil with a half-life of one to seven months. It is best to wait for the next growing season to add seed or plants in sites with Imazapyr treatment. A couple of sites were seeded and planted with native vegetation in 2021 and will continue to be monitored. MN DNR and MAISRC staff are now taking the lead on coordinating and funding invasive phragmites treatments throughout the state. They, local staff and volunteers will continue to use EDDMaps to report new sightings and follow up reports with treatment details so that invasive phragmites management will be documented and visible to all on the web-based system (Carrie Taylor, Anoka Conservation District).