Second Invasive Plant Found in Cobbosseecontee Lake

August 15, 2018

Contact: David Madore, Communications Director (207) 287-5842, or John McPhedran (207) 215-9863,

New plant seen in Maine for the first time

AUGUSTA, August 15, 2018 - On the heels of the recent discovery of Eurasian water milfoil, Maine Department of Environmental (DEP) has confirmed growth of another state-prohibited invasive aquatic plant in Cobbosseecontee Lake in Manchester. The plant, European frog's-bit (Hydrocharis morsus-ranae), is native to Europe and northern Asia and is a popular water garden and aquarium plant. First intentionally introduced to a water garden in Canada in 1932, the plant was found in a New York river in 1974 and continues to expand its range.

The Cobbossee find is the first known growth of this plant in Maine. European frog's-bit grows best in shallow, slow-moving water and sheltered coves which is where it was found in a cove and stream inlet in the northeast corner of the lake. The plant is well-established in the cove and stream, suggesting that it has been there for several years.

"Admittedly, this latest discovery it's a tough one-two punch for Cobbossee Lake. We don't know how the plant arrived in the lake but we have already begun the challenge of managing it," said John McPhedran, DEP Biologist. "The plant was discovered August 10, surveyed August 13 and removal began August 14. I am confident that DEP's collaboration with Cobbossee Watershed District and Friends of Cobbossee Watershed will result in reducing this infestation. But we also need to be realistic: real control will require continued commitment and will occur over years, not days or months."

In addition to reminding boaters to clean, drain and dry watercraft, trailers and equipment before launching and after removing from every waterbody, Maine DEP stresses that plants and fish from aquariums and water gardens should never be dumped into a stream or lake. If aquarium or water garden plants are no longer desired, throw them out with the trash.