Invasive plant

Oriental Bittersweet: A Bitter Beauty!

Article By: Jaqi Christopher, Invasive plant specialist & Mary Bartkowiak, Invasive plant coordinator

Just as the leaves begin to shift from summer green to the fall shades of gold, orange, red and bronze, the fruits of Oriental bittersweet explode on the scene with their very own show-stopping colors of bright gold and red.

The sight of these vines full of colorful berries may tempt the casual observer to take these berry-filled branches home to use as fall decorations or to plant in their own garden. This, however, would be a mistake, as this striking plant is a serious threat to native ecosystems. Oriental bittersweet is a restricted species under Wisconsin’s Invasive Species Rule NR40. This makes it illegal to transport, transfer or introduce Oriental bittersweet statewide.

Oriental bittersweet is an aggressive-growing woody vine that invades forests, woodlands, fields and hedgerows. The vines twine up trees, smother the crown and girdle trunks with their thick woody stems. In fact, the sheer weight of the vine can cause tree crowns to break and collapse and whole trees to uproot. Additionally, large mats of bittersweet can shade out native plants.

Oriental bittersweet woody vine twines up tree, girdling tree trunk

Oriental bittersweet vine girdles tree trunks. Photo Credit: Minnesota Department of Agriculture

Oriental bittersweet woody vine twines up tree, girdling tree trunk

Oriental bittersweet vine girdles tree trunks. Photo Credit: University of Illinois’ Chris Evans














Continue reading “Oriental Bittersweet: A Bitter Beauty!”

Invasive Plant Management Factsheets

Tree-of-Heaven. Photo credit: Richard Gardner,

The Renz Lab at the University of Wisconsin-Madison Division of Extension has created a series of factsheets discussing the identification and control of many common invasive plant species problematic to natural areas.

Mechanical, cultural and chemical control methods are discussed in detail, including the effectiveness of the control method and appropriate rates and timings of chemical control applications.

Continue reading “Invasive Plant Management Factsheets”

Wild Cucumber Will Catch Your Attention

Plants that are pokey, viney or spread quickly across the landscape sometimes seem alarming when you discover them in your backyard or woods or when they’re spotted along the highway. Wild cucumber has all these characteristics but is not as ominous as it seems.

Wild cucumber (Echinocystis lobata) is a vine native across the U.S. and found throughout Wisconsin. It has maple-like star-shaped leaves and has pale greenish-white flowers from July through September. A single plant is self-fertile but can also be pollinated by bees, wasps and flies. It produces a pod-like fruit with spikes resembling a cucumber which is unsafe to eat. Each pod produces four seeds that fall to the ground when the pod is ripe. The pods may persist into the winter and become thin brown shells.

Star-shaped leaves, pale flowers, and cucumber fruit of wild cucumber. Photo: Bugwood

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Giant Hogweed: Rare But Harmful

By Bernie Williams, DNR Invasive Plant Specialist. or 608-444-6948. 

Giant hogweed is a non-native, invasive plant that has gradually gained a foothold in the northeastern U.S. Once popular for its massive size and white umbrella-like flowers, it was introduced as an ornamental as early as 1917. Now known for its harmful blisters, it is recognized as a public health hazard and controlled wherever possible.

Characteristic purple blotches and white hairs on green stem of giant hogweed. Photo credit: Herkulesstaude_Fritz Geller-Grimm

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Wisconsin DNR 2020 Forest Health Annual Report

By Elly Voigt, DNR Forest Lab Technician and Communications Specialist,

The cover page of the 2020 Annual ReportThe Wisconsin Department of Natural Resources’ Forest Health team recently completed the 2020 Forest Health Annual Report. The report summarizes impacts from pests, diseases and weather on the health of Wisconsin’s forests. Highlights from 2020 include:

• An update on emerald ash borer in Wisconsin, including newly confirmed counties
• New township detections of oak wilt
• Flooding and tornado damage
• Summary of state nursery studies

For access to the report, visit the link here.

Nominations Open For “Invader Crusader” Awards

By Tara Bergeson, DNR invasive species team leader, 608-264-6043,

Nominations are being accepted through March 23, 2020 for “Invader Crusaders.” These awards go to individuals, groups and organizations who made outstanding contributions in 2019 to prevent, control or eradicate invasive species that harm Wisconsin’s native wildlife and wetlands, forests, prairies, lakes and rivers.

The Wisconsin Invasive Species Council is seeking nominations for exemplary efforts at addressing issues surrounding terrestrial and aquatic invasive plants and animals. The awards will be presented in both volunteer and professional categories.

To submit a nomination, download and fill out a nomination form available on the Wisconsin Invasive Species Council’s Invader Crusader webpage. Email the completed form to by March 23.

A panel of Wisconsin Invasive Species Council members will review the nomination materials and select the award winners. All nominators and winners will be notified by mid-May 2020.

Recipients of the awards will be recognized at an awards ceremony on June 11 at Olbrich Botanical Gardens in Madison.

Invasive species are nonnative plants and animals that cause great ecological, environmental or economic harm, and some can even affect human health. Once an invasive species becomes established in an area, it can be difficult to control. The most important action Wisconsinites should take is to avoid moving invasive species or the materials that might harbor them to new places.

To learn more about what you can do to stop the spread of invasive species, visit the DNR invasive species webpage.

2019 Forest Health Annual Report now available

Forest health annual report now available for 2019.

The Forest Health Annual Report summarizes notable impacts for that year of pests, diseases and weather on the health of Wisconsin’s forests. The report is a collaborative product created 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 2019 annual report include:

  • Dramatically increased decline and mortality from emerald ash borer in southern WI
  • New county and township detections of oak wilt
  • Precipitation record and major storm damage
  • Summary of state nursery studies on Diplodia sapinea, galls on jack pine seedlings, and testing new fumigants to replace methyl bromide

This year’s annual report is available on the DNR forest health homepage. Previous annual reports, including historical reports dating back to 1951, are archived and available upon request. Contact your local forest health specialist if you’d like digital copies of any archived annual reports.

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!”