Lake Independence Citizens Association

Curlyleaf pondweed (CLP) is an invasive plant that has spread across over 700 Minnesota lakes – including Lake Independence. It has curly, wavy leaves and can grow up to 15 feet tall.

 

This plant can cause significant problems for the environment and recreational activities in our lakes. CLP aggressively displaces native aquatic vegetation, thriving in early spring when most native species are still dormant. By early summer, the plant dies back—unlike native vegetation that dies off in the fall—releasing large amounts of phosphorus into the water. This nutrient release is a major trigger for toxic blue-green algal blooms, which cloud the water, reduce oxygen levels, and can result in beach closures and harm to aquatic life

 

Also, thick mats of curly-leaf pondweed can get tangled in boat propellers, fishing lines, and make swimming unpleasant. It covers large areas of the lake, making it hard to enjoy activities like boating, fishing, and swimming.

 

There are many management strategies to control CLPW, mechanical harvesting, chemical treatments and scientists are looking into using natural predators, like certain types of insects, to control curly-leaf pondweed but this method is still being researched and is not widely used yet.

 

We are preparing to take action on Lake Independence with a 5-year plan to control CLPW. Attend LICA’s Annual Meeting on April 26th to find out more information.

 

Here are some recent case studies and research findings on curly-leaf pondweed (Potamogeton crispus) and its association with algal blooms:

 

1. Gleason Lake, Minnesota (2007–2013)

A comprehensive study in Gleason Lake evaluated the effects of early-season endothall herbicide treatments over seven years. The treatments effectively reduced curly-leaf pondweed abundance. Interestingly, as curly-leaf declined, coontail (Ceratophyllum demersum) proliferated, potentially contributing to improved water clarity and reduced phosphorus levels. However, the study noted that while water transparency increased, the reductions in phosphorus and chlorophyll-a were not statistically significant.  University Digital Conservancy+2Taylor & Francis Online+2University Digital Conservancy+2

 

2. Lake Osakis, Minnesota

Lake Osakis has been grappling with curly-leaf pondweed infestations for decades. The Osakis Lake Association estimates that managing this invasive species costs approximately $200,000 annually. The pondweed not only impedes recreational activities but also contributes to algal blooms by releasing nutrients upon its mid-summer die-off.  Alexandria Echo Press

 

3. Bass Lake, Plymouth, Minnesota

In 2020, the Shingle Creek Watershed Management Commission initiated treatments in Bass Lake to control curly-leaf pondweed. The strategy involved early-season herbicide applications followed by alum treatments to bind phosphorus in the water column. This integrated approach aimed to curb algal blooms by reducing nutrient availability.  CCX Media

 

4. Belgrade Lakes Watershed, Maine

In 2022, curly-leaf pondweed was identified in the Belgrade Lakes Watershed, marking a significant ecological concern.Local organizations, including the 7 Lakes Alliance, collaborated with state agencies to assess the infestation's extent and develop management plans. Public awareness campaigns emphasized preventing the spread to other water bodies.  7lakesalliance.org

 

5. Research on Native Macrophyte Assemblages

A study by Ajay Robert Jones (2010) investigated the impact of repeated early-season herbicide treatments on native aquatic plant communities in Minnesota lakes. Findings indicated that while curly-leaf pondweed was effectively controlled, native plant species richness and biomass showed minimal changes, suggesting that multiple years of treatment might be necessary to observe significant ecological shifts.  University Digital Conservancy+1University Digital Conservancy+1

 

 

More resources about Curlyleaf Pondweed:

 

1. Minnesota Department of Natural Resources (DNR)

Provides information on identification, impacts, and management strategies.
Contact: Invasive Species Program
Phone: (651) 259-5100
Website: https://www.dnr.state.mn.us/invasives/aquaticplants/curlyleafpondweed/index.html

 

2. Minnesota Aquatic Invasive Species Research Center (MAISRC)

Researches distribution and control of curly-leaf pondweed.
Phone: (612) 626-1412
Website: https://maisrc.umn.edu/curlyleaf-pondweed

 

3. Wisconsin Department of Natural Resources (DNR)

Offers species profiles, fact sheets, and management tools.
Contact: DNR Invasive Species Program
Phone: 1-888-936-7463 (TTY: 711)
Website: https://dnr.wisconsin.gov/topic/Invasives/fact/CurlyLeafPondweed

 

4. Kansas Department of Wildlife and Parks

Monitors and manages aquatic invasive species.
Contact: Emporia Research Office
Phone: (620) 342-0658
Website: https://ksoutdoors.com/Fishing/Aquatic-Invasive-Species/Aquatic-Invasive-Species-List/Curly-Leaf-Pondweed

 

5. Maine Department of Environmental Protection (DEP)

Provides prevention and control guidance for aquatic invasives.
Phone: (207) 287-7688
Website: https://www.maine.gov/dep/water/invasives/curly_leaf.html

 

6. National Invasive Species Information Center (NISIC)

National clearinghouse for invasive species information.
Phone: (301) 504-5547
Website: https://www.invasivespeciesinfo.gov/aquatic/plants/curly-pondweed

 

Additional Reporting Tool

EDDMapS (Early Detection & Distribution Mapping System)
Submit curly-leaf pondweed sightings for regional tracking.
Phone: (706) 542-9031
Website: https://www.eddmaps.org/