Regulations

Avoid Hitchhikers This Summer

By Erika Segerson-Mueller, DNR invasive plant program specialist, Oshkosh
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Invasive jumping worms have a light-colored clitellum, while most worm species have a raised, pink clitellum. / Photo Credit: Brad Herrick, UW-Madison Arboretum

To reiterate some advice you may have heard long ago from your parents: Don’t give rides to hitchhikers. They may have been thinking about people, but hitchhiking invasive plants, insects and pathogens are also worthy of concern.

As you dream of days spent at the cabin up north, planting your garden or wandering in the woods, here are a few reminders to help you avoid bringing hitchhiking invasives along as you enjoy your spring and summer activities. Continue reading “Avoid Hitchhikers This Summer”

The Scourge Of Spurge, Both Cypress And Leafy

By Erika Segerson-Mueller, DNR invasive plant program specialist, Oshkosh;
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Photo showing the white milky sap of spurge plants, sometimes called “wolf’s milk.”

The white milky sap of spurge plants, sometimes called “wolf’s milk,” can be toxic to cattle and irritating to human skin. / Photo Credit: Norman E. Rees, USDA Agricultural Research Service Retired, Bugwood.org

Managing invasive plant species can really be a pain. When the plants you are targeting can potentially harm human health, that pain can become quite literal.

Leafy spurge (Euphorbia esula) and Cypress spurge (Euphorbia cyparissias) are restricted invasive plants under Wisconsin’s Invasive Species Rule NR40. Aside from their tendency to spread aggressively and displace native species, both plants contain a white milky sap that can cause skin irritation in some humans and is potentially toxic to cattle and horses. Continue reading “The Scourge Of Spurge, Both Cypress And Leafy”

On The Outs With Goutweed

By Erika Segerson-Mueller, DNR Invasive Plant Program Specialist, Oshkosh Service Center;
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Photo of Bishop’s goutweed, a common garden ornamental that may be better known to home gardeners as “snow-on-the-mountain.”

A common garden ornamental, Bishop’s goutweed may be better known to home gardeners as “snow-on-the-mountain.” / Photo Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

Introduced as an ornamental plant commonly planted in gardens, Bishop’s goutweed is a restricted invasive plant in Wisconsin under Invasive Species Rule NR40.

Also known by common names such as snow-on-the-mountain, bishop’s weed and goutwort, the variegated variety with white edges will probably look familiar to many gardening enthusiasts. Continue reading “On The Outs With Goutweed”

Dropping The Aphid Grenade On Garlic Mustard

By Erika Segerson-Mueller, DNR Invasive Plant Program Specialist, Oshkosh Service Center;
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Photo showing that leaves appear wrinkled and less healthy in garlic mustard plants affected by aphids.

Leaves appear wrinkled and less healthy in garlic mustard plants affected by aphids. / Photo Credit: Rebecah Troutman, Holden Forests and Gardens, Bugwood.org

The NR40-restricted invasive plant garlic mustard (Alliaria petiolata) is prevalent in many Wisconsin woodlands, but a new wave of hope is on the horizon.

The garlic mustard aphid, a tiny, dark, gray-to-green insect sometimes called the “grenade” aphid after the pattern of raised blotches on its back, was found in 2021 at the Holden Arboretum in Ohio. It could become a viable form of biocontrol for the garlic mustard plant.

Continue reading “Dropping The Aphid Grenade On Garlic Mustard”

Forget About Planting Forget-me-nots

By Erika Segerson-Mueller, DNR Invasive Plant Program Specialist, Oshkosh Service Center;
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Wide-angle photo of a forest road covered by a blanket of Woodland forget-me-not.

A forest road is covered by a blanket of Woodland forget-me-not. / Photo Credit: Caleb Slemmons, National Ecological Observatory Network, Bugwood.org

These easy-to-grow, sweet-sounding, small blue flowers may seem appealing, but you should forget about forget-me-nots. A garden plant frequently found in mixed bouquets, forget-me-nots can easily escape the confines of a garden and spread aggressively.

There are two species regulated as invasives in Wisconsin: an Aquatic forget-me-not (Myosotis scorpiodes) and Woodland forget-me-not (Myosotis sylvatica). Both species are restricted under Wisconsin’s Invasive Species Rule NR40, so control is encouraged if they are found on your property. These species cannot be transferred, transported or introduced without a permit.

Both the aquatic and woodland species of forget-me-not bloom in early spring and can share many visual characteristics. Continue reading “Forget About Planting Forget-me-nots”

‘In The Weeds’ With Invasives Tech

By Erika Segerson-Mueller, DNR Invasive Plant Program Specialist, Oshkosh;
Erika.SegersonMueller@wisconsin.gov or 715-492-0391

Photo of popular garden plants including tulips and daffodils.

While not native to the Midwest, popular garden plants such as tulips and daffodils do not spread outside of gardens or cause harm, therefore they are not invasive. / Photo Credit: Lesley Ingram, Bugwood.org

As the conversation around invasive plants grows, it’s easy to get “stuck in the weeds” when it comes to invasive terminology.

A simple Google search of “invasive plant” will produce a variety of definitions, bringing in technicalities or muddying your understanding with each new idea of what invasive means. Continue reading “‘In The Weeds’ With Invasives Tech”

Beware Of Bittersweet In Fall Decor

Photo of round leaf bittersweet berries

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

By Erika Segerson-Mueller, Invasive Plant Program Specialist, Oshkosh Service Center;
Erika.Segersonmueller@wisconsin.gov or 715-492-0391

When temperatures begin to cool and back-to-school sales emerge, our thoughts turn to pumpkin spice, sweater weather and all things fall décor.

But as you gear up for spooky season this year, the Wisconsin Department of Natural Resources (DNR) reminds you to beware of using invasive plants in your decorations.

Continue reading “Beware Of Bittersweet In Fall Decor”

Douglas County Joins Spongy Moth Quarantine

A spongy moth larva eats a leaf.

A spongy moth larva eats a leaf.

By Paul Cigan, DNR plant pest and disease specialist
Paul.Cigan@wisconsin.gov or 715-416-4920

In early April, Douglas County became the 53rd Wisconsin county added to the state’s spongy moth quarantine list after a discovery that the invasive insect (formerly known as gypsy moth) had become established in the county.

The United States Department of Agriculture-Animal and Plant Health Inspection Service (USDA-APHIS) and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) made the determination based on results of a monitoring program of adult moths and other life stages.

Continue reading “Douglas County Joins Spongy Moth Quarantine”