Rogues Gallery: Get to know the invasive species threatening our lakes
2025 Invasive Species Committee Report
2025 LEA Hancock Pond Survey Report
2025 LEA Sand Pond Survey Report
Download & print the "Most Unwanted Aquatic Invasive Plants" Poster
Rogues Gallery of Maine's Invasives
Photos & information from the Lakes Environmental Association's website
Variable Leaf Milfoil
Variable-leaf milfoil (VLM) is the most common invasive aquatic plant in Maine, found in 49 waterways in the state. You can find more information about VLM and how the Lakes Environmental Association is working to combat it by clicking here.
In addition to Variable Leaf Milfoil, there are 7 other invasive aquatic plant species found in Maine's lakes and rivers.
Eurasian Watermilfoil
This species of water milfoil was first discovered in a small pond in Maine in 2003. It is also found in nearby Massachusetts, Vermont, New Hampshire, Connecticut, and the Canadian Provinces. Once introduced into a lake, Eurasian water milfoil is virtually impossible to eradicate. It grows rapidly and aggressively, reproducing primarily through fragmentation.
The introduction of one single fragment of this plant can result in the infestation of an entire lake. Learn More.
Hydrilla
Hydrilla was first found in Maine in Pickerel Pond in 2002 by a landowner. While that infestation has been successfully eradicated,Hydrilla is native to Africa and is considered the most problematic invasive plant in Hydrilla is a prolific weed that forms stems reaching up to 30 feet in length. It is able to dominate freshwater ecosystems quickly when fragmented by boat props and by way of winter buds, underground tubers, and surface runners. Hydrilla can not only out-compete native aquatic plants, it can infest a lake more aggressively than variable water milfoil, the most common invasive plant established in Maine.
European Frogbit
European frog’s-bit is a free-floating plant with clustered heart-shaped leaves. White flowers with three petals and yellow centers bloom in the summer. It grows in dense mats that block light to native plants. As they decay these mats deplete oxygen needed by fish
They also impede recreational water activities like swimming, boating, and fishing. European frog’s-bit has been reported in Maine, Vermont, New York, and several Canadian provinces.
Curly Leaf Pondweed
Curly-leaf pondweed is a submerged plant with strap-shaped leaves, similar to many of Maine’s native pondweeds. However, unlike our native pondweeds, Curly-leaf pondweed leaves are distinctly ruffled with finely serrated edges. It grows in large dense beds.
This species was confirmed in a small pond in southwestern Maine in 2004. It is also present in nearby Massachusetts, New Hampshire, Vermont, Connecticut, New York, and Rhode Island.
Invasive Naiad (Brittle Waternymph)
European naiad is arguably the most difficult invasive plant to control in Maine. Herbicide treatments and manual removal efforts are being used in Northeast and Milton Ponds on the border with New Hampshire. This plant's tiny seeds can stick to the sides of boats, and get into bilge water, and are nearly impossible to spot. Thoroughly cleaning and draining your boat and trailer, especially when leaving these infested lakes, is critical to preventing the spread to new waterbodies.
Parrot Feather
Parrot feather has two types of leaves: robust green wax-coated emergent leaves arranged in whorls around the stem and submersed leaves that may appear brown and decaying. Tiny white flowers grow in the leaf axils of emergent stems. Parrot feather is native to South America . It grows well in both fresh and mildly saline waters and can survive on dry banks and shores. Plants sprout from overwintering rhizomes in the spring. Thick growths of parrot feather may impede swimming, boating and fishing.
Swollen Bladderwort
Swollen bladderwort (Utricularia inflata) is a free-floating, submerged plant native to The Atlantic and Gulf coastal plains. This species can be quite invasive, becoming dominant in ponds and displacing other native aquatic plants. U. inflata reproduces by fragmentation and seeds and can easily spread to new locations and new waterbodies. A small piece of the plant can be transported by fishing gear, boats, trailers, and duck hunting decoys. The submersed vegetative part of the plant overwinters under the ice and begins growing again in spring.
Boat Inspections are Critical
The greatest threat we face is milfoil infestation. The risk is real. Lake Arrowhead, Songo River, Sebago Lake, Brandy Pond, and Long Lake - all in our vicinity - are battling milfoil infestations. Many boaters who visit those lakes also visit ours.
For this reason, Courtesy Boat Inspections at the Hancock Pond boat launch is a vital deterrent. In the past, paid inspectors checked boats on weekends from Memorial Day through Labor Day, with Mondays and Fridays added during holiday weekends.
Donate to Increase Our Boat Inspections
HSPA Invasive Species Committee Report 2024
In the Spring of 2023, the Invasive Species Committee (Mike Gately, Chair, and Dave Rogers) learned from the Lakes Environmental Association (LEA) that continuing boat inspections between Labor Day and the second week of October is a smart investment, as boat traffic continues to be heavy and invasive plants continue to grow. Mike and Dave tried to cover boat inspections through volunteers last year. However, they found it to be difficult to find volunteers after Labor Day. This year, Mike and Dave propose adding paid boat inspections for five weekends beyond Labor Day. The LEA recruits and trains the inspectors, but we pay their salaries. We are pleased to report that Mike has successfully secured a 2024 grant from the Maine Department of Environmental Protection (DEP) of $3,000, up from $2,530 last year. That is a major accomplishment given the stiff competition for those funds. This year our proposed cost for expanded boat inspections, after the DEP grant, will be $5,510, an increase of $1,874.
Your donation will help fund boat inspections at the Wabunaki Road boat launch. Last year, you donated $2.525. for which we thank you very much!
Our goal this year is to raise a total of $4,400, which will cover the additional $1,824 in inspection fees.
Please donate to our Invasive Species Fund.
