Colony of EWM in Little Glen Lake in 2024, before burlap barrier treatment began.
History of EWM in Little Glen Lake
Floating strands of EWM were first discovered in Glen Lake in 2023. By summer of 2024, the GLA identified a small, but growing, cluster of EWM colonies in Little Glen. In hopes of achieving complete eradication, the GLA considered diver-assisted suction harvesting and chemical herbicides.
“Our team quickly discovered those methods have never proven 100% successful in any lake where they’ve been applied,” said Kate Gille, executive director of the GLA. “We wanted to implement a technique that would completely eradicate EWM instead of managing its growth.”
By the spring of 2025, the EWM infestation covered roughly 570 square feet of Little Glen Lake.
The GLA began collaborating with the Grand Traverse Band of Ottawa and Chippewa Indians (GTB) on an eradication effort, as the GTB holds treaty rights within its territory to hunt, fish, gather, and actively manage natural resources. This includes habitat restoration through invasive species removal.
Together, the GLA and GTB installed biodegradable burlap barriers to block sunlight and kill EWM at the root. Over time, the burlap degrades naturally, which allows native plants to regrow.
“There has been notable success with the burlap method on Lake Leelanau. It’s a highly targeted, effective approach,” said Gille. “We’re deeply grateful to the GTB for their shared commitment in this fight to remove EWM from the watershed. Their expertise and leadership make them a natural and invaluable collaborator for us.”
But the fight isn’t over. Last summer, the GLA identified additional strands of EWM growing at the treatment site. However, this was expected because the plant fragments easily and may also send out sprigs to the edge of burlap barriers in search of sunlight. A dive team quickly secured a new set of micro burlap barriers.
The GLA continued to survey the watershed for new infestations, using a drone and underwater remotely operated vehicle (ROV) to investigate 25 sites with suspicious growth across Big Glen, Fisher Lake, and Brooks Lake.
“The results were thrilling—we found no new EWM colonies in 2025!” Gille said.
Ongoing Management to Protect Glen Lake
This year, the GLA’s eradication work in Little Glen will continue. As the burlap barriers natural decompose, the team will begin monitoring them in late June to check for recurring EWM, as well as native plant regrowth. If more EWM strands are found this summer, the GLA will deploy additional burlap barriers in collaboration with the GTB.
The GLA will also perform another comprehensive drone scan to compare the locations and sizes of aquatic gardens with measurements from previous years. Any sites suspected of EWM growth will be identified and investigated further using underwater ROVs in August.
“It’s like when you go to the dermatologist and they need to check any new skin spots for your health,” explained Rob Karner, watershed biologist for the GLA. “We use the drones to look for new spots of concern in the lake. If they look suspicious from the skies, we then investigate underwater to confirm if EWM is present.”
Later this summer, the GLA is also rolling out a new EWM Community-Based Monitoring Program. Participants will help serve as the ‘eyes and ears’ of the watershed. “They’ll walk their shorelines to watch for plant fragments that wash up and report any suspicious findings,” Karner said.
In the meantime, watershed stewards, visitors, and residents can help keep an eye out for EWM. It looks similar to native watermilfoil, but there are key differences. Look for:
- Limp leaves that float near the surface or bend easily when removed from the water (native watermilfoil is stiffer)
- Reddish or pink stems (native watermilfoil stems are whiteish-green)
- Whorled leaves with 12 or more pairs of leaflets per leaf (native watermilfoil has only 5-10 pairs)
If you think you found EWM, note with wind direction, save the wet plant in a resealable plastic storage bag, and contact the GLA to confirm identification: rob@glenlakeassociation.org