Invasive plants found in the Mississippi River - KXLT - Fox 47 Rochester MN News, Weather and Sports

BUFFALO CITY, Wis. (FOX 47) -- The U.S. Fish and Wildlife Service and the Department of Natural Resources have been battling several invasive species.

Three invasive plants have now shown up in a portion of the Mississippi River near Buffalo City, Wis.

In 2011, nearly 1,500 water hyacinth and water lettuce plants were removed and destroyed from a dozen locations on the river.

The invasion was thought to be over. But in one location 10,000 are back, along with a new one: the parrot feather.

It has since been removed, but the bay will still get a chemical treatment early next week.

Experts say the plants are a serious threat to natural wildlife.

"They do not belong in the Mississippi River and they can out-compete native vegetation because there's no natural predators for them here," said Mary Stefanski of Upper Mississippi River National Wildlife and Fish Refuge. "That's our goal is to completely stop it from spreading any further."

Stefanski said the plants are common choices for home koi ponds and someone may have put them in the river, causing the infestation.