Great Lakes aquatic invasive plant continues its march into Michigan’s inland waters

European Frog-bit has been discovered in several new locations

Lilly pads in a pond
The small heart shaped leaves and white flowers of European frog-bit.| Photo by Erick Elgin.

Be on the lookout this summer for a dainty water lily look-alike that packs a punch.

European frog-bit is an aquatic invasive plant that has been in the coastal areas of Lake Erie, Lake Huron, and Lake St. Claire for years. However, in 2016, it was unexpectedly found in Reeds and Fisk Lakes in Grand Rapids. Since then, it has been discovered in several additional inland waterbodies.

European frog-bit (Hydrocharis morsus-ranae) is a free-floating aquatic plant with multiple miniature lily pad shaped leaves. Originally from Europe and Asia this plant produces dense, floating mats that can cover large areas of shoreline. These mats can hinder recreation, reduce waterfowl and fish habitat, and reduce light conditions for beneficial native aquatic plants.

Due to the threat that European frog-bit poses to our lakes and ponds, it is on Michigan’s Aquatic Invasive Plant Watch List. As AIS Awareness Week kicks off in Michigan, this is the perfect time to become familiar with European frog-bit. You can help fight the spread of this species by: (1) learning how to properly identify it, (2) knowing how to report any sightings, and (3) preventing spread by following the clean-drain-dry-dispose guidelines for your recreational equipment

Following these actions, coupled with ongoing eradication efforts by the State of Michigan, can help prevent European frog-bit from becoming a familiar sight in Michigan’s waters. 

How to identify European frog-bit?

European frog-bit is predominately free-floating, meaning it rarely roots to the bottom of a waterbody. The leaves look like miniature lily pads, about the size of a silver dollar. In contrast, Michigan’s native water lilies have sturdy roots anchored to the waterbody bottom and have much larger leaves. 

Key features to look for:

  • Free-floating plant with leaves that arise from a single point
  • Leaves are round/heart shaped and resemble little (0.5 – 2.25 inches) water lilies
  • Leaves have a dark purple underside with a spongy area around the midvein of the leaf
  • White flowers with three petals and a yellow center

For more identification tips see the MISIN European frog-bit fact sheet.

How to report a sighting

If you find European frog-bit, or even suspect that you have, contact the Department of Environment Great Lakes and Energy Aquatic Invasive Species Program at EGLE-WRD-ANC@michigan.gov or call 517-284-5593.


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