Keep a Look Out for Japanese Stilt Grass!

Japanese stilt grass is an annual grass that has been spreading very quickly through the eastern and southern parts of the US in the last 10 years. It germinates in late spring and grows to 6+ feet, sprawling across other vegetation and forming a dense mat. In addition to blocking out light and killing tree seedlings and understory plants, it alters the nutrients and drastically alters fire behavior in forests and grasslands. Stilt grass produces a large amount of fine fuel that causes very high temperatures, high flames and very complete (not patchy) burns. Seedlings can continue germinating all summer and plants that germinate as late as August can produce seed before frost kills the plants. Seed production is very high. Seedling density can be as high as 150 seedlings per square inch.

The current known range of stilt grass is from New England and New York to Texas. In the Midwest it is not yet known north of Indianapolis, but it's presence in New York indicates it would likely thrive in Wisconsin. We do not want this plant spreading in the upper Midwest, so it is up to everyone to keep a look out for it. If you see anything that fits it's description, go to one of the websites listed below to ID it or send in a specimen or photo to determine what it is. Look for a sprawling grass with short leaves (3-5") that come off at right angles from the stem. The key ID characteristic is a silver stripe of hairs down the middle on the upper side of the leaves.

When it is found in the state it will need to be controlled before it develops seed that first year. Be certain to locate the entire population and look in the vicinity for other possible patches. Hand pulling can be effective for small patches and mowing or weed whacking for larger patches, but return to the site several weeks later to be sure all plants have been removed. Burn or otherwise dispose of any plants that have begun developing seeds. Grass specific herbicides can be effective if used in late summer but before seed development.

Anyone finding Japanese stilt grass, or any other invasive plant listed as prohibited under DNR's new NR 40 invasive species rule, should contact the DNR's Invasive Plant Coordinators right away. You can email invasive.species@wi.gov or call Kelly Kearns at 608-267-5066 or Tom Boos at 608-266-9276. Do your part to look for this plant and make sure it gets contained before Wisconsin's forests are overrun by an invasive that makes garlic mustard look easy!

WEBSITES FOR MORE INFORMATION:
WI DNR's fact sheet
Management recommendations by the primary stiltgrass researcher
WI DNR's list of prohibited and restricted invasive plants

The River to River CWMA short video showing the impacts of stilt grass and how to ID it.