The keen eye and natural curiosity of a University of Minnesota Extension Master Naturalist led recently to the discovery of an invasive species not seen in the United States for six decades. Thanks to her, efforts are now underway to prevent it from overtaking other vegetation in Stearns County.
The invasive species is called rough potato (Metaplexis japonica), a type of vining milkweed, and it was spotted by Master Naturalist Sherry Kutter on the Lake Wobegon Trail near Holdingford. At the time, she was enjoying a trek with her grandchildren, Corva and Cisco. Unfamiliar with the plant, they photographed it and uploaded the image to iNaturalist, an app that identifies plant and animal life and aids in global research.
“Honestly, I don't think I would have noticed this plant had I not been spending extra time exploring outside with my grandkids during the pandemic this summer. They’re fascinated with discovering new things in nature and we've spent time together photographing plants and insects and sharing them on iNaturalist when we couldn't make an ID. When we loaded photos of this vine, it came up as a plant apparently not even in the U.S., so I was intrigued,” Kutter says.
Native to eastern Asia, rough potato was last spotted in cornfields near Iowa State University in Ames in 1958. The Minnesota Department of Agriculture (MDA) notes it may have been part of a research project during World War II.
There are no vining milkweeds native to Minnesota. Rough potato climbs aggressively and can easily overtake vegetation.
“You don’t want invasive species like rough potato to be in your environment but you do want to know if they’re here,” says Amy Rager, Extension educator who oversees the Master Naturalist program. “In this case, we can hopefully get it under control because it was found and we’re guardedly assuming this is still rare.”
Because of the magnitude of the infestations, the Stearns County Parks Department, Conservation Corps Minnesota (CCM), and MDA began removing thousands of seedpods, each containing many seeds. This was done to prevent the infestation from spreading. Based on experience with related vining milkweeds, a combination of herbicide treatment and manual removal over several years will bring down the infestations.
“While we may never know how rough potato got to Stearns County, we can be diligent so this and other invasive plants don’t spread throughout Minnesota,” says Monika Chandler, MDA invasive species specialist. “Seeds and plant parts like to hitch a ride, so cleaning equipment, pets, and our clothes before leaving an area can help prevent the spread of unwanted plants.”
The discovery exemplifies Minnesota’s leadership in empowering volunteers to look for invasive plants and aquatic species, Rager notes.
This article features information from the Minnesota Department of Agriculture. If you see a vining milkweed, which has a distinctive milkweed seedpod, report it to the MDA’s Arrest the Pest line at firstname.lastname@example.org or 1- 888-545-6684. Work done by CCM and the MDA was supported by the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizens Commission on Minnesota Resources.