Water lettuce was found on the Clinton River  spillway in September.

Water lettuce was found on the Clinton River spillway in September.

Photo provided by the Lake St. Clair CISMA


Watch out for water lettuce on the waterways

By: Kristyne E. Demske | C&G Newspapers | Published November 17, 2020

 McKenzi Waliczek, coordinator of the Lake St. Clair Cooperative Invasive Species Management Area, looks for invasive water lettuce on the Clinton River Spillway in October.

McKenzi Waliczek, coordinator of the Lake St. Clair Cooperative Invasive Species Management Area, looks for invasive water lettuce on the Clinton River Spillway in October.

Photo provided by the Lake St. Clair CISMA

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MACOMB COUNTY — It’s a plant that might look pretty in a contained pond or water feature in a yard, but not spreading freely over the surface of the Clinton River.

Unfortunately, that’s where water lettuce has been spotted this fall.

Staff from the Clinton River Watershed Council were conducting routine water quality monitoring in September when someone spotted a single water lettuce plant in the Clinton River Spillway. Water lettuce is a free-floating invasive aquatic plant on Michigan’s invasive species watch list, a list of species that have never been confirmed in the wild in Michigan or have a limited known distribution. Water lettuce leaves are spongy, grayish-green and occur in circular patterns that can spread up to 18 inches across. It has freely hanging, feathery roots that can reach up to 20 inches long and propagates when the horizontal stems are broken from a parent plant, so it can be spread by water recreation, fishing equipment and other activities that can cut the plant into pieces.

McKenzi Waliczek, Lake St. Clair Cooperative Invasive Species Management Area (CISMA) coordinator, said they have conducted several surveys since its discovery to determine the extent of the infestation.

“We have found it from Gratiot Avenue all the way to Lake St. Clair,” she said. “It is a little bit beyond just the spillway. Every day we’re finding new areas of it.”

The group is not sure how the water lettuce got into the river and spillway. It is a legal plant available at landscaping centers, but it is only allowed to be used in contained ponds, not anything that is “confluent with any public waterways.”

The Lake St. Clair CISMA serves Macomb and St. Clair counties.

Each Michigan county has a CISMA, which works cooperatively with communities, including county governments, nonprofit organizations and universities. The CISMAs are funded through the Michigan Invasive Species Grant program.

“Collectively we, as a partnering agency, work to manage invasive species, raise awareness of invasive species and their impacts” on local environments, and “locate and prevent invasive species from spreading further than they are already naturally doing,” Waliczek said.

So far, 115 individual plants have been identified and removed from the Clinton River and the spillway.

“The Lake St. Clair CISMA was very quick in their response to the MISIN report,” said Clinton River Watershed Council watershed ecologist Eric Diesing in a statement. “Invasive species can harm our local water resources in many ways, and I am glad we were able to catch this one early.

“CRWC will continue to work with the LSC CISMA to address this issue into the future.”

Aquatic invasive species are estimated to cause $5.7 billion of damage in the Great Lakes region every year.

“Yes, you can purchase this plant, yes you can have it at your home, however, it is not allowed to be released,” Waliczek explained. “It is unlawful to be dumping this into public waterways.”

There are steps owners must take to properly dispose of it at the end of the season, she said, either by drying it out and placing it with waste headed for a landfill — not in the compost — or by burning it.

“This is a floating plant, so it has extreme mobility compared to a lot of other plants. It propagates really quickly,” she said. “It is actually considered one of the world’s worst weeds.”

If water lettuce invades a waterway, it can get to a level where it covers the entire surface of the water, restricting sunlight into the water and indirectly affecting what vegetation grows in the water and, thereby, the level of oxygen in the water for fish and other aquatic wildlife.

“It’s kind of like a snowball effect,” Waliczek said.

It’s important for people to report if they spot water lettuce or another invasive species out in the wild. They can do so through the MISIN app, available for free in the Apple and Google Play app stores, or by visiting www.michi gan.gov/invasives.

“Without those little bits of information, this could have gone unchecked for who knows how long,” Waliczek said.

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