11/1/2018 4:17:00 PM Invasive phragmites: Locals
gear up to act sooner than later
There were 50 or 60 people at Chisago Lake Township Hall October 25 wanting to learn more about what’s being done to address non-native phragmites australis.
The reed chokes-out shorelines, farm fields and ditches on roadsides.
Dense groupings of phragmites have been identified at 86 sites in Chisago County. Thanks to activist lake association members here, the invasive plant has been brought to the public’s attention. The reason there’s so many known infestations is probably because people in Chisago County are looking for the plant. According to the MNPhrag group data provided at last week’s meeting, there are 130 phragmites sites in the state; so right now more than half are in this county. (You can download the ‘ed maps’ application and see phragmites sites. If you know of a grouping of plants that isn’t mapped you can put the site onto the app too.)
It’s possible, according to a researcher who spoke at last week’s meeting, that the growing season in the northern third of the state isn’t sufficient for the plant to thrive, but this is still being studied.
The non-native plant is undesireable because it takes away areas of habitat for amphibians, aquatic mammals and fish. It crowds-out native plant species and reduces biodiversity. It is a fire hazard in certain locations, and it impacts agriculture operations. It impedes recreation when you have to hack through a thicket to find a shoreline or boating lane.
Phragmites australis can regenerate itself from small pieces of stem, from rhizome runners, or seeds from its large purple-ish seed spray atop the stalk.
People are cautioned not to move around cut-up stalks or disturb seed heads if they take plants down. You can tightly bag them or burn them carefully so fragments of plant don’t travel.
The best time of the year, when seeds are well-attached and not likely to be sent in a million directions has passed for this year.
Any mechanical harvester use, like equipment for below surface lake weeds, is not effective because it just disperses pieces that regenerate into more plants.
Invasive phragmites can be eradicated, but it’ll take a concerted effort, according to U of M researcher Julia Bohnen, from the MNPhrag group. Bohnen said the east side of Wisconsin is fighting its infestations with herbicide sprayed from helicopters.
Hopefully; if Minnesota gets ahead of the proliferation, the costs can be contained along with the spread.
Bohnen stated, “The good news is that there’s a whole lot of people here who care about this.”
She told the audience. “The areas we have identified are what I consider manageable.”
Meanwhile, the state is reviewing the official designation of phragmites australis and in 2019 the designation could change.
Minnesota law recognizes two designations of noxious weeds-- if a weed is listed as restricted the landowner is not required to manage it. If a weed is listed as prohibited, the landowner must control it, or the government will do it for them and assess costs. At this time, phragmites australis is restricted.
The MNPhrag group is coming together to develop a statewide response plan and to facilitate plant management. At this point management is going to be private and local, Bohnen explained.
The Chisago Lakes Coalition of Lake Associations has many volunteers, however, who are eager to help you identify or figure out how to approach an infestation. Contact your local lake association leadership.
The Chisago County Soil & Water Conservation District is available to possibly be a drop site-- if people want to have plant samples looked at for I.D. The funding and programs established currently through the SWCD are aimed at control of lethal agricultural weeds right now, according to Casey Thiel of Chisago County’s SWCD, but the organization is willing to do what it can.
Bohnen explained the state will be training certified professional chemical applicators on phragmites australis eradication, at a seminar this winter.
What can you do? The recommendation currently, based on phragmites research so far, is to first get your plants identified. Bohnen said there are non-native decorative grasses and reeds that resemble the autralis species, but won’t become invasive. Watch for details in the paper on central I.D. sites or call a lake association member.
The association for Lindstrom and Chisago lakes can be reached at firstname.lastname@example.org. North and South Center Lakes property owners can reach out at INFO@CENTERLAKES.ORG.
Best practices The protocol for eradication involves herbicide use between end of August and end of September. Treating with chemicals after frost won’t be effective.
The products (glyphosate or imazapyr) should be used with an aquatic surfactant so the chemical adheres to the plant.
The cutting or mowing phase is recommended six to eight weeks before chemical application. It will be June before mowing is recommended. You can go out on the ice for prep in winter time. Take-off plant parts above the lake surface-- but Bohnen said you have to be extra careful that no plant pieces remain on the ice and to bag and seal seed heads right away. The runners and rhizomes can be attacked with herbicide or by physical removal later.
Bohnen said she is no fan of chemical use but “...we can’t do everything mechanically.”
The eradication process could take multiple seasons, she added. Three years of treating is recommended at this time.