Invasive plant

Invasive plants, ticks and you

Most people are familiar with the impacts of invasive plants to natural areas, but did you know that invasive plants can be hazardous to human health? Did you also know there is a new app available to learn about tick activity near you and help researchers by recording your own tick encounters?Forested setting with tree in foreground and sign attached to tree that says beware of ticks. Continue reading “Invasive plants, ticks and you”

Slow the spread by sole and tread – revisited!

By Mary Bartkowiak, invasive plants specialist, Rhinelander,, 715-493-0920

There’s so much to enjoy about fall and so many activities to take in before the blanket of snow changes our landscape. Something to keep in mind is that the introduction of invasive plants can play a role in changing the landscape, too.

Slow the spread by sole and tread - logo and image of boots that could carry invasive seed Continue reading “Slow the spread by sole and tread – revisited!”

Invasive plant management on roadsides workshops

Invasive plants have been shown to impact Wisconsin’s economy, environment and human health. Roadsides are a key area where these unwanted plants establish and spread. These right of way habitats are challenging to work in but focused efforts can be successful in preventing spread and reduce invasive plant populations.

To help educate and jumpstart management, The University of Wisconsin-Madison Extension along with 4-Control are conducting roadside invasive plant workshops throughout the state. We invite you to attend one of these five regional workshops. While this training is available to anyone interested, the focus will be on training staff of municipalities that manage vegetation on roadsides. Continue reading “Invasive plant management on roadsides workshops”

2018 Forest Health Annual Report now available

The Forest Health Annual Report summarizes notable impacts pests, diseases and weather on the health of Wisconsin’s forests. The report is a collaborative product written by DNR forest health specialists from around the state. It outlines the damage and spread of both native and invasive pests and diseases during that year and puts these into context of observations from previous years. Management programs and their results are also described. Highlights from the 2018 annual report include:

  • American beech with resistance to disease-causing scale insect entered into a breeding program for species conservation and reintroduction
  • Confirmation of jumping worms in northern counties
  • Biological control of emerald ash borer
  • Closure of the state gypsy moth suppression program
  • Innovation in survey of the invasive plant lesser celandine
  • Dieback and mortality in balsam fir caused by freezing weather in April followed by unseasonably hot temperatures in early May

The 2018 report and others dating back to 2003 are available on the forest health publications page. Historical reports dating back to 1951 are archived and available upon request. Contact Marguerite Rapp at for more information on the archived reports.


Planning Boosts Forest Health and Management

From the kitchen table to the boardroom table, the USDA brings people together across the nation for: healthier food, natural resources and people; a stronger agricultural industry; and economic growth, jobs and innovation.

Each Friday, meet those farmers, producers and landowners through their #Fridaysonthefarm stories. Visit local farms, ranches, forests and resource areas where USDA customers and partners do right and feed everyone.

Click here to read the full story about Jay and Mike Carlson, a father-son team working with NRCS in the Driftless Area to identify management goals that are helping improve the way they manage their forests and its health.

Photo: Honey bees are pollinating wildflowers on the Carlson’s property.

Be on the lookout for lesser celandine

By Michael Putnam, DNR invasive plants specialist (Madison),, 608-266-7596

Lesser celandine flower

Lesser celandine flower. Photo: Wikimedia

Lesser celandine (Ranunculus ficaria) is an invasive forest plant that been found in urban forests in southeastern Wisconsin. The plant has a history of taking over forest floors in the eastern U. S. and crowding out native plants and tree seedlings. Consequently, lesser celandine is listed as a Prohibited Species under the state’s invasive species law NR 40, and cannot be transported, sold, introduced or possessed in Wisconsin.

DNR is undertaking control projects in Dane, Milwaukee, Racine and Kenosha counties – four of the six counties where lesser celandine is known to occur – and will be conducting surveys in the remaining two counties, Walworth and Waukesha, to inform future control efforts.

Lesser celandine with reproductive bulbils

Lesser celandine with reproductive bulbils Photo: DNR photo

Lesser celandine starts growing in early spring, with bright yellow flowers appearing in April. It dies back by the end of June. This low-growing plant has shiny, waxy leaves that are kidney or heart-shaped. Small spherical bulbils that form along the stems drop off to give rise to new plants, while underground tubers sustain the plant after it dies back. Because of its short growing season, DNR depends on reports from the public to identify new populations to plan accordingly. If you encounter this plant, please report it at


Giant hogweed (Heracleum mantegazzianum)

Giant hogweed. Photo by Donna Ellis.

Giant hogweed. Photo by Donna Ellis.

Giant hogweed can be a threat to human health. Its sap has Furocoumarins (photosensitizing compounds) that can cause a skin reaction known as phyto-photodermatitis. This makes the skin highly sensitive to ultraviolet light. Swelling and blistering of the skin may lead to permanent scarring, and contact with the eyes can cause temporary and sometimes permanent blindness.

In Wisconsin, giant hogweed is classified as a prohibited species under the Invasive Species Rule (Wis. Adm. Code ch. NR 40). Its presence potentially causes economic or environmental harm or harm to human health. Isolated populations of Giant hogweed have been found in Wisconsin with immediate control taking place after verification.  Continue reading “Giant hogweed (Heracleum mantegazzianum)”

Amur cork tree is an emerging threat to Wisconsin forests.

Amur cork tree (Phellodendron amurense) is a relatively new invasive plant found in at least four Wisconsin counties. It is classified as Prohibited under Wisconsin’s invasive species law, NR 40. The female cork tree cannot be possessed, transferred, transported or introduced in Wisconsin. We ask that you report this tree to DNR because it is invasive here and in other states and DNR is mounting control efforts before it becomes widespread. DNR works with property owners to achieve this by providing advice, tools and resource opportunities. Continue reading “Amur cork tree is an emerging threat to Wisconsin forests.”

Lesser celandine is an emerging threat to Wisconsin forests – be on the lookout.

Spherical bulbils of lesser celandine form during the spring growing season. Later they drop off and sprout to form new plants.

Spherical bulbils of lesser celandine form during the spring growing season. Later they drop off and sprout to form new plants.

Lesser celandine (Ranunculus ficaria), also known as fig buttercup, is a ground layer plant and an aggressive invader of forests in North America. So far, it is relatively unknown in Wisconsin but has been found in the southeastern part of the state, especially in moist (mesic and wet-mesic) forests and along river banks.

Lesser celandine is a spring ephemeral that emerges in early spring, develops flowers, dies back by early summer, and remains dormant in underground tubers. During the short growing period the plant produces bulbils which sprout and give rise to new plants. After the round bulbils drop off they are spread by gravity, water, small animals, and like the tubers, transported when soil is moved. Continue reading “Lesser celandine is an emerging threat to Wisconsin forests – be on the lookout.”