Invasive Plant Management

Aquatic Invasive Plant Management

Variable milfoil management on Squam

In 2000, variable milfoil (Myriophyllum heterophyllum​) was discovered in the Squam Lakes. Since that time, the Squam Lakes Association has tirelessly worked to keep this submerged invasive aquatic plant controlled. Our efforts have proven to be successful; there has not been a new infestation of variable milfoil identified on the Squam Lakes since 2007. While our efforts mainly focus on variable milfoil, we also keep an eye out for any other invasive plants that may try to sneak their way into Squam.


Throughout the summer, we staff both the public boat launch on Route 113 in Holderness and our own Piper Cove launch with Lake Hosts. Lake Hosts greet boaters as they enter and leave the lake, education boaters of the dangers and locations of aquatic invasive species, and offer to perform a voluntary boat inspection to ensure that no plant material is traveling on boats as they enter and exit the lake.

Interested in volunteering to be a Lake Host? Click here for more information.

Early Detection

Though the Squam Lakes have been managing variable milfoil infestations since 2000, there are a host of other aquatic invasive plants that are circulating the area. Weed Watchers, dedicated volunteers that search the lake for invasive aquatic plants, are key in identifying potential invasives before they become a problem. Download the Frightful Fourteen, a publication from the NH Department of Environmental Services, to learn more about other invasive species that have been spotted both in the state and regionally. Here is a presentation from NH DES that outlines the Weed Watcher program and the invasive species that are seen throughout the region, but are not yet found in Squam.

Interested in volunteering as a Weed Watcher? Click here for more information.

Weed Watcher Volunteer Report Form


Variable milfoil (Myriophyllum heterophyllum​) is currently the only invasive species that is found in the Squam Lakes.

Learn more about the SLA's efforts in the management of variable milfoil on Squam.


Visit our web links page to learn more about aquatic invasive plants in New Hampshire.

Terrestrial Invasive Plant Management

There are a number of terrestrial invasive plants in the Squam Watershed. The Squam Lakes Association is partnering with other area conservation groups to identify the locations of invasive plants and to create an action plan to manage these infestations.

Visit our web links page to learn more about terrestrial invasive plants in New Hampshire.