European frog-bit

Harmful Impacts

European frog-bit reproduces rapidly, forming dense mats on the surface of the water. These mats can interfere with boat traffic and other recreational activities, as well as, reduce oxygen and light levels in the water column altering food and habitat for wildlife.

European frog-bit is an aquatic invasive plant on the state of Michigan’s watch list. It is important to prevent, detect, and quickly control watch list species because if left unchecked they can spread rapidly with many negative impacts to the environment and economy.

Local Efforts

Beginning in 2022, the Lake St. Clair CISMA started monitoring for European frog-bit in Macomb and St. Clair counties. We have been monitoring waterways throughout the counties by kayak, powerboat, and waders and reporting our findings to EGLE. We plan to propose treatment options for certain locations in the following year.

How You Can Help

  • Some invasive species are legally designated by the State of Michigan as either "prohibited" or "restricted." If a species is prohibited or restricted, it is unlawful to possess, introduce, import, sell or offer that species for sale as a live organism, except under certain circumstances.

  • Clean boats, boat trailers, fishing equipment, waders, and other gear to prevent spread.

  • Report observances to the Midwest Invasive Species Information Network or notify your local CISMA.

European frog-bit Identification

  • Free-floating aquatic plant sometimes rooted in shallow water.

  • Leaves are small, 0.5-2.5 inches, round to heart-shaped, with a purple-red underside.

  • Single flower with three white petals and yellow center may be visible from June to August.