Invasive plant

Make Plans For National Invasives Week

Workers spray water from a hose to clean the wheels of a tractor in a woodlot.

Workers follow the practice of pressure-washing the tires and frames of a tractor to rid the vehicle of possible invasive plants after a workday in the forest. / Photo Credit: Wisconsin DNR

By Art Kabelowsky, DNR Outreach and Communications
Arthur.Kabelowsky@wisconsin.gov or 608-335-0167

The North American Invasives Species Management Association (NAISMA) has organized a series of activities to take place as part of its National Invasive Species Awareness Week (NISAW), set for Feb. 23 through 27.

The Wisconsin Department of Natural Resources will participate by presenting a news release and daily social media posts in the days leading up to the start of NISAW’s 2026 activities.

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Correction On Plans For Discarding Holiday Decorations

A pile of discarded Christmas trees in a drop-off lot.

A stack of discarded Christmas trees awaits processing at a drop-off facility. / Photo Credit: Wisconsin DNR

By Wisconsin DNR

An article in the January edition of the Wisconsin Department of Natural Resources’ Forest Health News contained some incorrect information on the disposal of wreaths, trees, boughs and other holiday decorations.

The article focused on disposing holiday plant matter in ways that avoided the spread of invasive insects, seeds and spores that can spread to harm trees, plants and habitats.

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Be Mindful Of Invasives During Holiday Clean-Up

A stack of discarded Christmas trees awaits processing at a drop-off facility.

A stack of discarded Christmas trees awaits processing at a drop-off facility. / Photo Credit: Wisconsin DNR

By Wisconsin DNR

Invasive plants and insects don’t mind playing the long game. After all, they’re just trying to survive and thrive, like the rest of us.

They’ll hang out as part of your holiday decorations throughout the season, just on the chance humans might dispose of them improperly, giving them an opportunity to find a new home in your yard or neighborhood.

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Invasive Species Action Awards Nominations Open

A group photo showing the winners of the 2025 Invasive Species Action Awards, given by the Wisconsin Department of Natural Resources.

Winners of the 2025 Invasive Species Action Awards, given by the Wisconsin Department of Natural Resources. / Photo Credit: Wisconsin DNR

By Wisconsin DNR

The Wisconsin Department of Natural Resources (DNR) has announced that the Wisconsin Invasive Species Council will accept nominations for the 22nd annual Invasive Species Action Awards through Feb. 15, 2026.

Award recipients are Wisconsin residents and organizations who have made significant contributions to prevent, control or eradicate invasive species that harm Wisconsin’s native forests, wildlife, wetlands, prairies, lakes and rivers.

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Beware Of Invasive Plants In Your Holiday Décor

The berries of round leaf bittersweet grow in clusters at each leaf axil and are beautiful, but this highly invasive plant makes it unsuitable for use in your fall decorations.

The berries of round leaf bittersweet (Celastrus orbiculatus) grow in clusters at each leaf axil and are beautiful, but this highly invasive plant makes it unsuitable for use in your fall decorations. / Photo Credit: Chris Evans, University of Illinois, Bugwood.org

By Wisconsin DNR

With the holiday season drawing near, it’s time for the Wisconsin Department of Natural Resources (DNR) to remind home crafters to be wary of using invasive plants in fall and winter decorations.

While holiday decorations made from natural materials can be beautiful, some wreaths and other home decorations may contain invasive species.

A quick Google or Pinterest search for décor ideas brings up a slew of orange-tinged images: pumpkins, leaves, pinecones and pretty fall foliage — sometimes boasting small, red-orange berries. While you can safely cloak your home in most of these items, avoid the one with the red-orange berries, as it likely comes from the non-native, woody vine called round leaf bittersweet (Celastrus orbiculatus, previously known as Oriental bittersweet).

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Invasive Japanese Stiltgrass Detected In Three More Counties

Wide-angle photo of a mat of Japanese stiltgrass in Rock County, Wisconsin, in July 2025

A mat of Japanese stiltgrass in Rock County, Wisconsin, in July 2025. / Photo Credit: John Zaborsky, University of Wisconsin-Madison Renz Weed Science Lab

By Wisconsin DNR

Thanks to the help of eagle-eyed observers across southern Wisconsin, the harmful invasive plant Japanese stiltgrass (Microstegium vimineum) has now been detected in three additional counties. That brings the total number of Wisconsin counties to five.

The most recent detections of the non-native, annual grass came in Dane, Grant and Walworth counties. The Dane County find was in Middleton, northwest of Madison; in Grant County, it was found southeast of Wyalusing State Park; in Walworth County, it was found north of Geneva Lake.

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Autumn Is A Great Time To Treat Invasive Plants

By Wisconsin DNR

Photo of rosettes on a garlic mustard plant. / Photo Credit: Wisconsin DNR

Rosettes on a garlic mustard plant. / Photo Credit: Wisconsin DNR

As temperatures begin to fall the leaves of many plants and trees have begun to change color. Some trees in the northern part of the state have already started to drop their leaves.

The Wisconsin Department of Natural Resources (DNR) reminds the public that fall is more than a great time to enjoy the changing hues in the woods. It also presents a good opportunity to spot the invasive plants persisting among the native plants and trees.

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DNR, UW Offer Fall Invasive Plants Workshops

Buckthorn beneath dead ash trees at Big Foot Beach State Park. / Photo Credit: Wisconsin DNR

By Wisconsin DNR

Is buckthorn taking over your urban property? Would you like to be able to determine which plants are doing harm to the native landscape? Are you ready to arm yourself in the fight against invasives?

If so, this day-long workshop is for you!

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Invasive Plant Japanese Stiltgrass Detected In Rock County

A wide-angle photo showing a mat of Japanese stiltgrass growing in Rock County, Wisconsin, in July 2025.

A mat of Japanese stiltgrass growing in Rock County, Wisconsin, in July 2025. / Photo Credit: John Zaborsky, University of Wisconsin-Madison Renz Weed Science Lab

By Wisconsin DNR

The harmful invasive plant Japanese stiltgrass (Microstegium vimineum) has been detected in a private woodland near Beloit in Rock County, according to a blog post made Monday by the University of Wisconsin-Madison Extension.

It is the second detection of the non-native annual grass in Wisconsin. The first took place in 2020, inside the Coulee Experimental Forest in La Crosse County. The Wisconsin Department of Natural Resources  (DNR) has been working to eradicate that population.

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Invasive Species – Fall Workshops

By Olivia Witthun, DNR Urban Forestry Coordinator; Olivia.Witthun@wisconsin.gov or 414-750-8744

The Wisconsin Department of Natural Resources is partnering with the UW-Madison Division of Extension to host a series of fall workshops on invasive species plant identification and management. Learn about invasive plants in urban settings, focusing on identification, impacts, management and available resources. Dr. Mark Renz (professor and Extension specialist with UW-Madison) will lead the instruction, with Travis Wilson, Matt Wallrath and John Zabrosky assisting. Each workshop will include morning classroom instruction followed by hands-on field demonstrations in the afternoon. The cost of the workshop is $40 and includes lunch. Continue reading “Invasive Species – Fall Workshops”