Managing Eurasian Watermilfoil
Protecting Gilmore Lake through monitoring, prevention and active managmement
What is Eurasian Watermilfoil?
Eurasian watermilfoil, often called EWM, is an invasive aquatic plant that can spread rapidly through lakes and waterways.
It grows below the water's surface and forms dense mats that may crowd out native aquatic plants, interfere with boating, fishing and swimming, and harm fish and wildlife habitat.
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EWM spreads primarily through plant fragments. Even a small piece carried on a boat, trailer or other water equipment can take root and establish new growth.
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Because EWM spreads so easily, early identification and removal are critical. Lake residents can play an important role by learning what to look for and monitoring the water around their own shoreline.
Look for feather-like leaves arranged in whorls of four to six around a reddish stem. Each leaf typically has 12 to 20 pairs of slender leaflets. When the plant is held out of the water by its stem, the leaves appear limp and collapse against the stem.
Our EWM Management Plan
Eurasian watermilfoil was first identified in Gilmore Lake more than 25 years ago. Since then, the Gilmore Lake Association has maintained an ongoing commitment to keeping this invasive plant in check and limiting its spread.
Managing EWM on Gilmore Lake presents a particular challenge because of the lake's native wild rice beds, which are protected under federal treaties with Native American tribes. These protections can limit the use of aquatic herbicides in areas where EWM and wild rice coexist, making a flexible, targeted approach especially important.
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Today, the GLA's EWM management plan focuses on three key areas:
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Monitor and map EWM throughout the lake. Professional surveys help identify where EWM is present, track changes in its distribution and guide management decisions.
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Remove EWM with the most appropriate methods. Depending on location and conditions, management may include diver-assisted removal, careful hand-pulling of isolated plants and herbicides, pending permit approval from the DNR.​​​​​​​​
Emily Moore of Moore Lake & Garden LLC shows Gilmore Lake residents how to identify Eurasian watermilfoil (EWM) and properly hand-pull small patches around the lake.
The goal is not to eliminate every EWM plant—an unrealistic expectation once an invasive species becomes established—but to keep it under control, limit its spread and protect the health of Gilmore Lake.
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​Prevent further spread. Education, signage and strategically placed buoys help residents recognize EWM, avoid infested areas and reduce the movement of plant fragments to other parts of the lake.​​​​​​
How You Can Help Protect Gilmore Lake
Learn to identify EWM. Become familiar with Eurasian watermilfoil and other aquatic plants in the lake. Native plants can help create a natural barrier to EWM spread, so it's important to avoid unintentionally removing beneficial species.
Keep watch along your shoreline. Scoop up floating EWM fragments before they can take root elsewhere. Small plants can also be carefully hand-pulled from the lake bottom and removed from the water.
Help prevent the spread. Pay attention to buoys and signage marking EWM-infested areas, and avoid boating through dense patches whenever possible. Clean all boats, trailers, and equipment to prevent transporting plant fragments.
​​Use caution in the North Basin. More than 13 acres at the north end of Gilmore Lake are infested with EWM. Watercraft can cut plants into fragments that easily spread and take root in other parts of the lake.
​​Support GLA's stewardship efforts. Membership dues and contributions to the Preservation Fund provide critical local funding and help GLA secure grants for EWM management and other lake stewardship initiatives.
​Be hopeful and patient. Progress is possible, but reducing EWM will take time, effort, and ongoing community commitment.
