Winona County Top 5 Invasive Species


This most wanted list will be periodically updated with information and tools on combating a wide variety of invasive species within our county. For more information on treatment and eradication plans check out the online resources.

If you have additional comments or questions, please email us.Arrest the Pest

Tracking Infestations

To learn more about reporting and tracking new infestations, check out Arrest the Pest.

Oriental Bittersweet

Oriental Bittersweet has occurred in Winona County more than any other county in the state of Minnesota and has become a top priority for treatment and eradication. A partnership between private landowners, the city of Winona, Winona County, and the state is essential to successfully eliminate Oriental bittersweet. Treatments were initiated in 2014 and will continue through 2018. This work is supported by the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizens Commission on Minnesota Resources. This invasive species is very similar to the native American Bittersweet plants that are popular with crafters for decorative purposes. Check out the videos below to learn how you can identify Oriental Bittersweet and how to manage it properly.

Oriental bittersweet is a damaging invasive plant pest, but it's easy to confuse with another plant. Special thanks to project funders: U.S. Farm Bill and the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizens Commission on Minnesota Resources.

Defeating A Killer Vine

Bittersweet Identification for Crafters

University of Minnesota Extension forester Angie Gupta explains the differences between American bittersweet and Oriental bittersweet. Crafters should only use American bittersweet. Oriental bittersweet is an invasive species.

Photos are courtesy of the Minnesota Department of Agriculture. Copyright 2013 by the Regents of the University of Minnesota.

Japanese Knotweed

Japanese Knotweed has been spotted in several locations within Winona County, as well as surrounding areas. This leafy plant may look pleasant, but can quickly outpace the growth of native species that cannot compete with the plant for space. The Mn Department of Agriculture has created a handy Homeowner's Guide to help you combat the spread of Japanese Knotweed.

Wild Parsnip

Wild Parsnip is a toxic and invasive species. Infestations are common along roadways, and this seemingly pleasant looking plant can cause severe skin burns if exposed to sunlight. Proper handling is important when removing wild parsnip. Wear protective clothing including long pants, long sleeves, closed shoes, gloves, a hat, and eye protection. Avoid activities such as weed whipping which can cause sap to fly.

Skin Burn

Emerald Ash Borer

The Emerald Ash Borer (EAB) is a terrestrial invasive beetle that feeds on white and black ash trees that are native to Winona County. It is theorized that the EAB was transported to the Detroit area in wooden shipping crates. Since then it has been quickly spreading across the Midwest. Tree removal and replacement have become a major cost for communities both large and small.

Community education and involvement are integral in combating the spread of Emerald Ash Borer. It is illegal to transport hardwood firewood out of Minnesota quarantined counties unless it is MDA-certified firewood.

Hunting for Emerald Ash Borer

European Buckthorn

European Buckthorn was originally brought to North America by early settlers and used as decorative hedging. It is a fast-growing shrub that can destroy native vegetation rapidly. Minnesota is home to one of the largest infestations of buckthorn nationally and is working to combat its spread.

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