Curly-leaf pondweed. A silly name, but a not-so-silly threat to Lake Leelanau. This aquatic invasive species is the latest invader in Lake Leelanau, with impacts similar to those of Eurasian watermilfoil. Discovered in Lake Leelanau in 2023, the Lake Leelanau Lake Association (LLLA) has been working to control the two small infestations on the lake, but we need your help to spot new infestations and keep them from spreading into sensitive areas, like the Cedar River. Please read this week’s article to learn about this threat to Lake Leelanau and what you can do about it.
The Problem
Similar to Eurasian watermilfoil, curly-leaf pondweed (CLP) is an aquatic invasive species that causes recreational, economic, and ecological damage, which can affect how residents and visitors use and enjoy Lake Leelanau. Impacts of curly-leaf pondweed include:
- Forming dense mats at the water’s surface that inhibit water recreationists.
- Overtaking habitat and outcompeting native aquatic plants, potentially lowering diversity.
- Providing unsuitable shelter, food, and nesting habitat for native animals.
- Littering the shoreline with dead plants during midsummer die-offs.
Like Eurasian watermilfoil, CLP reproduces through fragmentation and sexual reproduction when its flower spikes grow to the surface. However, CLP has some reproductive superpowers that make it even more dangerous. CLP has an additional reproductive structure, called a turion, that can lie dormant in the sediment for extended periods before sprouting to form new plants. When the plant starts growing early in the spring, it produces the turions, which often lie dormant through the summer and germinate in the fall, giving CLP two growing periods per season. Double the trouble!
Curly-leaf Pondweed in Lake Leelanau
There are two areas of Lake Leelanau where curly-leaf pondweed has been identified. One is in the Narrows and the other is the mouth of the Cedar River. Both of these areas are very shallow, making your boat's propeller susceptible to getting tangled in CLP and transporting it to other parts of the lake.
Attention Boaters in the Narrows and Cedar River
If you take your boat through either the Cedar River or the Narrows, we ask that you please trim your motor up and inspect your propeller to ensure there are no plants caught on it. If there are plants attached to it, please remove them and dispose of them on land, not in the water!
The 548 acres of the Cedar River and its surrounding wetland are protected by the Leelanau Conservancy. The Cedar River, sometimes called the "Everglades of Michigan’s Lower Peninsula", hosts a large and diverse range of plants and animals and is the largest inlet into Lake Leelanau. The river and its wetlands act as a filter, providing clean and clear water to Lake Leelanau. The underwater native vegetation provides important habitat for young fish and other insects and species that make up our native ecosystem, giving us a healthy and ecologically diverse lake. You can learn more about the Cedar River and the Leelanau Conservancy's efforts to protect it here. Though the land is protected, the water is still accessible and at risk from impacts caused by humans. Please do your part to protect this ecological gem of Leelanau County.
How to Identify Curly-Leaf Pondweed
Curly-leaf pondweed has some key identifying characteristics that make it easy to identify.
- Lasagna noodle leaves: This is what gives CLP the name. The edges of the leaves are wavy, just like lasagna noodles, and are 2-4” long with a red mid-vein in the middle and a smaller vein on either side of the larger mid-vein.
- Serrated edges: If you hold the plant up to the light, you will see on the edges that there are tiny serrations or “teeth”.
What YOU Can Do
Report It!
Here comes the big question: What to do if you spot a plant you suspect is curly-leaf pondweed or another aquatic invasive species? Please report it to us! LLLA has developed an easy-to-use digital form to submit findings if you suspect you have identified an AIS. If one of our biologists believes it could be an AIS of concern, we will contact you to investigate further.
Prevent the Spread
Curly-leaf pondweed and other aquatic invasive species easily spread from lake to lake on boats, kayaks, waders, and other watercraft. Please be sure to always CLEAN, DRAIN, DRY your boat and equipment when you move from Lake Leelanau to a different water body and vice versa! Lake Leelanau has 4 boat cleaning stations around the lake to make this easy for you. Click here to learn more about our boat cleaning stations.
Thank you for doing your part to help us keep Lake Leelanau clean and beautiful for all.
Main Photo Credit: Jim Wysor