On Monday, August 25, the Horticulture Division of UW- Madison stated that two more counties in the southern half of Wisconsin were found have stilt grass.
Japanese stilt grass is an invasive species known for aggressively taking over forests and natural habitats as it crowds out native species.
Over the past two weeks, the UW team has found two new infestations of stilt grass, raising alarm about its potential spread throughout the state.
In one instance, the grass was located on a piece of private property in Walworth County. In the other instance, the grass was found on a piece of private property in Grant County.
Teams have asked individuals in southern Wisconsin to stay vigilant as this could potentially become a threat throughout the area.
They have explicitly stated that people in Rock, Grant, Lafayette, Walworth, Green, and Kenosha counties should be on high alert and inspect their grass.
Individuals have been encouraged to send photos of possible stilt grass infestations found both on private property and in woodland areas, such as public parks.
The grass can be identified by its sprawling habit, delicate stems, and distinct leaf shape. The leaves are often lance shaped, alternating as they travel along the stem, and are typically between 1 and 3 inches in length.
Due to the fact that Japanese stilt grass is not native to the area, its introduction poses a serious threat to Wisconsin’s ecosystem.
It is known to grow in wide, large beds across forest floors, near lakes and streams, and can very easily spread into yards.
Stilt grass has been a problem in Illinois for years, but in 2025 it has started to spread north from southern Illinois into regions of the state that are in close proximity to the Wisconsin border.
The species was first identified in the early 1900s, where it likely came over from Asian countries when it was used as a packing material. Until recently, it has typically only been found in the southeastern portion of the United States.
According to professor Mike Renz, a weed specialist at UW- Madison, “It makes wildfires more frequent and severe, alters nutrient cycling and soil microbes, and reduces wildlife habitat, all of which decreases biodiversity.”
