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Invasive Aquatic Plants

  • Invasive aquatic plants are non-native species that take over and eradicate native species. As a result, entire habitats are disrupted, which can lead to water quality issues and many other issues. 

  • China Lake is VERY FORTUNATE: there is NO evidence of invasive aquatic plants currently being in our lake. Let's keep it that way! 

    • CLEAN off any mud, plants, and animals from boat, trailer, motor and other equipment. Discard removed material in a trash receptacle or on high, dry ground where there is no danger of them washing into any water body.

    • DRAIN all water from boat, boat engine, and other equipment away from the water.

    • DRY anything that comes into contact with the water. Drying boat, trailer and equipment in the sun for at least five days is recommended if rinsing your boat, trailer parts and other equipment with hot, high pressure water is not an option.

  • FYI, the Clean, Drain and Dry methodology was signed into Maine law on June 16, 2023

Reporting Suspicious Plants

If you believe you have encountered one of the species described in the table below, get in touch w/Maine Department of Environmental Protections' Invasive Aquatic Species Program.

Species & Locations
What are watermilfoils? 

​Watermilfoils are rooted, submerged aquatic plants found naturally in lakes and streams. Five varieties of watermilfoils are native to Maine and are part of the natural lake ecosystem. Two non-native watermilfoils threaten the quality of Maine fresh waters; Variable leaf milfoil (myriophyllum heterophyllum) is already present in 27 Maine lakes systems, including streams. Eurasian watermilfoil (myriophyllum spicatum), the more aggressive colonizer of the two, has been found in several Maine water bodies.

Where do they come from and how do they spread? 

All invasive species have a native habitat somewhere, many invasive aquatic plants were first transported as ornamental aquarium plants. When aquaria were emptied into lakes or streams, the plants proliferated in their new environment. Variable leaf milfoil was first recorded in Maine in 1970 in Sebago Lake. 

Additional Resources

Demystifying Milfoil (PDF) - Lake Stewards of Maine, 2019

Variable-leaf Milfoil Physical Characteristics


  • Whorls of 3 to 5

  • Mostly about 0.05-0.09 inches apart on stem

  • Rarely reach 0.59 inches long

  • All but lower bracts are shorter than flowers


  • Whorls of 4 on the axils of bracts


  • 4-lobed

  • Almost spherical


  • Horizontal stem

  • Branching leafy shoots about 8.1 feet long

  • Reddish-brown in color


  • Branch from horizontal stem

Sources: Lakes Environmental Association, WeedersDigest

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