This is the third in a monthly series on invasive plant species in Northern Michigan, their impact on natural landscapes and what can be done to help control and prevent their spread.

A tiny, floating plant that can dominate entire shorelines of ponds, lakes and slow-moving rivers is here in Northern Michigan — and it is spreading fast.

European frog-bit is a free-floating aquatic plant, about the size of a quarter, that grows in colonies and forms dense mats on the water’s surface. It prefers areas that are sheltered from wind and waves, particularly shallow spots near shore where other vegetation like reeds or cattails offer it protection.

Mats of frog-bit make it difficult or impossible for fish, waterfowl and other wildlife to move through infested areas. Additionally, any plants or insect larvae trying to live underneath frog-bit mats die due to the lack of sunlight and oxygen. Dead and decaying matter makes oxygen-poor conditions worse.

“It can completely alter an aquatic ecosystem,” said Rachel Leggett, Heartland Restoration Team Lead for Huron Pines.

Perhaps the most dangerous attribute of frog-bit is its ability to spread quickly. Floating plants can drift across a lake or downstream in a river and establish new colonies. A single plant, if left stuck to the hull of a boat or kayak, can start a whole new infestation when introduced into another body of water. It’s no coincidence that frog-bit is often found near public-access sites and kayak launches.

“People may not even realize it’s an invasive species when they’re paddling through it,” Leggett said. “That’s why it’s so important to clean, drain and dry your watercraft or waders after each trip.”

Boaters, paddlers, anglers and waterfowl hunters can avoid spreading invasive species like frog-bit by cleaning their boat, trailer, waders and gear after each trip. Drain your watercraft on site, remove all vegetation from your watercraft and trailer, and allow your boat and gear to dry completely between outings. You can also use 409, a household cleaning product, to kill any organisms that may be hiding on equipment.

Treating infestations of frog-bit on a waterbody requires removal by hand or rake. This needs to be done with care to ensure no plants escape and drift away from a removal site. Plants can be left on shore to dry in the sun or bagged for disposal.

Suspected infestations can be reported to the Midwest Invasive Species Information Network (MISIN) at misin.msu.edu.

The Huron Coastal Invasive Species Network is made up of conservation groups, landowners, state and federal agencies that seek to restore native habitat through invasive species education, prevention and management. The Huron Coastal ISN is led by Huron Pines with support from the Michigan Invasive Species Grant Program (Michigan.gov/Invasives).