Rhamus cathartica common buckthorn (above) - Photo credit: Melinda Meyers

Help Stop the Introduction of Invasive Plants into Wisconsin Gardens
by Melinda Myers

“Defending our Health by Stopping the Spread” is this year’s focus for National Invasive Species Awareness Week (NISAW), Feb 23-27, 2026. This international event is designed to increase awareness about invasive species. Who better to enlist in this effort than gardening influencers like you?

As you plan your outreach efforts for February, consider including mentions of this important topic. Share the importance of avoiding the introduction of invasive plants to our landscapes and include helpful management strategies.  

Start your outreach efforts now as gardeners are busy browsing catalogs, reading garden articles and looking for sources of new plants. Encourage people to check their plant wish list for any invasive plants that are classified as prohibited or restricted in Wisconsin before placing any orders online.

Review Wisconsin’s Invasive Species Rule, Chapter NR40 with them. Explain that prohibited plants are those that are not currently found or occur in isolated areas in the state. If introduced into the state, these plants are likely to cause significant economic or environmental harm or harm to human health.  Restricted plants are already established in the state, causing harm or having the potential to cause significant harm. Neither can be bought or sold and prohibited plants cannot be possessed.

Although regulations for the sale, purchase and possession of invasive species are in place, some online sellers are not aware, not up-to-date or not concerned with following existing state and federal regulations.  Just because you can purchase a plant online does not mean it is allowed in Wisconsin. It is up to us, the individual gardener, to make sure invasive plants do not end up in our gardens, natural spaces and waterways.

Share with others the negative impact these plants have on their landscape and natural spaces. Growing even one or two invasive plants in your garden, shoreline planting or pond can make a big difference. Invasive plants can be vigorous growers and often reproduce faster than our native plants, negatively impacting them and the songbirds, beneficial insects and wildlife that depend upon these plants.

Sometimes we need to make it personal to help encourage action. Let gardeners know these plants also have a negative impact on their health. Invasive populations of honeysuckles, buckthorns and barberries form dense thickets with high humidity beneath the plants, a perfect environment for ticks. Researchers found an abundance of Lyme-disease carrying ticks in areas with dense barberry populations. Another study found the percentage of ticks collected in honeysuckle-infested woods with disease-causing bacteria was 10 times higher.  

Managing existing invasive plant populations can be overwhelming. Prevention is an easy and inexpensive first step in the battle against these problem plants. Help your followers avoid creating more work and expense for themselves while protecting our natural spaces by doing their research before purchasing plants this season.

When in doubt, check the invasive species page on the Wisconsin Department of Natural Resources website. Just enter the name of the plant in question to check its status in Wisconsin. This site also contains detailed information on identification, the ecological threat and management options for invasive plants.

You and your followers may also find the Strategies for Managing Invasive Plants webinar recording and handout useful. The handout contains an extensive list of free resources and links on this topic.

Remind gardeners to always dress appropriately and check for ticks when removing invasive plants or enjoying the outdoors. Tick checks done right after you come back indoors and a shower within two hours of time spent outside help reduce the risk of tick bites.

Thanks to all of you who are already spreading the word and actively trying to manage invasive terrestrial and aquatic plants. If you, members of your organization or followers are interested in volunteering to help control invasive plants, email DNRAISinfo@wisconsin.gov. Together we can make a difference!

Melinda Myers has written more than 20 gardening books, including the Midwest Gardener’s Handbook, 2nd Edition and Small Space Gardening. She hosts The Great Courses “How to Grow Anything” streaming courses and the nationally syndicated Melinda’s Garden Moment radio program. Myers is a columnist and contributing editor for Birds & Blooms magazine and was the Plant Doctor on WTMJ radio in Milwaukee for over 20 years. Myers’ website is www.MelindaMyers.com.