Invasives Management 

Exotic Aquatic Plants are not native to a particular area. New Hampshire is currently battling eight exotic species in lakes and ponds. Over seventy water bodies are now infected by exotic aquatic plants. These invasive plant species can reduce the recreational value of water bodies and decrease the economic value of waterfront property according to a 2001 study by the University of New Hampshire.


One of the most threatening aquatic species in the State of New Hampshire is milfoil. Since its first introduction in New Hampshire in the late 1960’s, variable milfoil (Myriophyllum heterophyllum) has infested over 60 water bodies. This species is not native to New Hampshire and is very difficult to control once it becomes fully established. Milfoil reproduces through fragmentation whereby plant fragments break off from the parent plants through wind or boat action, grow roots and settle in a new location. Milfoil can spread rapidly and when it does, often displaces beneficial native plant life. Eurasian milfoil ( Myriophyllum spicatum) is another non-native milfoil, but tends to be found in waters with higher pH ranges than those found in New Hampshire and is considered much less of a threat than variable milfoil.

What does it look like?

Milfoil is a submerged aquatic plant with fine densely packed, feather-like leaves surrounding a thick reddish main stem. Often found in calm, shallow water less than 20 feet deep, milfoil can grow up to 15 feet and may exhibit a 3 to 6 inch green spike flower above the waterline.

Does Silver Lake have milfoil?

Luckily, through our Weed Watcher and Lake Host programs, Silver Lake does not have an infestation of milfoil or other exotic plants species.