As the ice melts and the lakes open up, curly-leaf pondweed (CLPW) begins its rapid rise to the surface, forming dense mats that block sunlight from reaching plants lower in the water column. CLPW is a cold-hardy invasive aquatic plant that grows slowly beneath the ice throughout the winter and reaches peak growth in May and June.
Curly-Leaf Pondweed Key Points and Identification Tips
Curly-Leaf Pondweed Timeline
When we first discovered rooted CLPW in North Pond in 2024, large, dense patches had already formed by mid-May—while most native aquatic plants were just emerging from winter dormancy. This early growth strategy allows CLPW to monopolize valuable space and resources, crowding out native species and creating cascading impacts for fish and wildlife. For these reasons, early spring removal is critical to prevent the formation of dense monocultures that harm native biodiversity.
We are still in the early stages of understanding this infestation. In 2024, we observed a period of seasonal dormancy from mid-June through August, which coincided with a significant lake-wide algae bloom. In contrast, no such dormancy was observed in 2025, and CLPW appeared to grow throughout much of North Pond. With only two years of active management, there is still much to learn. What remains certain, however, is that 7 Lakes Alliance divers will continue working diligently to locate and remove this noxious species in order to protect North Pond.
In 2025, North Pond Association volunteers, anglers, and property owners played a vital role by keeping watchful eyes on the lake and deploying marker buoys to flag suspected CLPW. Their efforts allowed 7 Lakes divers to respond quickly to new sightings—our most effective strategy for limiting spread and reducing ecological impact.
Belgrade Lakes watershed Curly-Leaf Pondweed Timeline
Get Involved
The crew will return to the water beginning April 20 and continue through the end of October. You can expect to see them on the lake Monday through Thursday, with additional group paddles co-hosted with the North Pond Association on select summer weekends. If you spend time paddling, fishing, or boating on North Pond, we encourage you to become a CLPW spotter.
Become a CLPW spotter in three easy steps:
- Learn to identify the plant
- Drop a marker buoy when you find it
- Contact our Invasive Aquatics Director by phone or email with the location
Your help makes a meaningful difference in protecting the lake.
You can pick up buoys at 7 Lakes Alliance headquarters (137 Main Street, Belgrade Lakes) or at the North Pond boat launch when Courtesy Boat Inspectors are on site (May 22–September 7). We’re also happy to drop buoys right at your dock!
Report CLPW & request buoys:
Sharon Mann
Invasive Aquatics Director
7 Lakes Alliance
sharon@7lakes.org
(603) 205-3912 [text or call]
Sharon Mann
Invasive Aquatics Director
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