Arboretum News

Invasive Discovery: Japanese Stiltgrass

A researcher at the Horticultural Research Center found the invasive species in Wisconsin.

COVID-19 Update: The Minnesota Landscape Arboretum is open by reservation only. Find updates and information here.

Plant Conservation Program Botanist and Researcher Amanda Weise shows how to identify Japanese stiltgrass. Photo courtesy of Wisconsin Department of Natural Resources.

By Liz Potasek

Amanda Weise, a botanist and researcher in the Plant Conservation Program at the Minnesota Landscape Arboretum, was volunteering in the Northeast Coulee Oak Woodland Scenic Natural Area in Wisconsin when a patch of grass with a limey-green color and distinct white stripe down the center of its leaf caught her eye. She pulled up the specimen, noted the stilt-like roots, and recognized it immediately: Japanese Stiltgrass. “In the area where I am originally from, Japanese stiltgrass is a major problem and has become so widespread, it lines many road edges and fill forest understories,” says Weise, who moved to Minnesota from the East Coast. “It tends to become established in rich woodlands and flood plains, which are common in Minnesota and Wisconsin.”

Weise checked EDDMapS, an invasive species tracking website, and found that there were no verified reports yet in Wisconsin, so she submitted a report via the EDDMaps app on her phone. The Wisconsin Department of Natural Resources (DNR) quickly responded by sending staff to survey all the roads, trails and streams in the area. Weise was still on site, so she gave DNR staff a quick identification lesson. “Staff flagged every patch, recorded its coordinates and hand-pulled small patches,” according to a press release from the Wisconsin DNR. “Larger patches along the road and parking area were sprayed by DNR State Natural Area crew members. They will return every year to re-survey and treat the area until no more plants are found.”

Japanese stiltgrass stands out with bright lime green leaves and a noticeable white or clear stripe that runs down the center of each leaf. Photo courtesy of Wisconsin Department of Natural Resources.

Japanese stiltgrass is a damaging invasive plant that can spread rapidly. “Stiltgrass chokes out native plants, harms wildlife habitat and reduces tree seedling survival,” according to the Wisconsin DNR. “Patches of stiltgrass also create a highly flammable fuel source potentially leading to bigger and more intense wildfires.”

The grass has been found and is spreading in all states east and south of Wisconsin except for Maine. “We were very fortunate the Japanese stilt grass was spotted early by a person familiar with the plant and who knew how to report it,” says Kelly Kearns, Wisconsin DNR invasive plant specialist. “As a result, we were able to get out there and get on it. This was a textbook example of early detection and control, and why citizen reports of invasive species are so important.”

Weise’s work as a botanist and conservation researcher for the Plant Conservation Program means that she’s usually on the look out for rare plants to save. When she spotted the Japanese stiltgrass, she was volunteering to conduct surveys for the Wisconsin Rare Plant Monitoring Program.

She’s worked on the Plant Conservation Program at the Horticultural Research Center at the Arboretum since August of 2019. “We focus on the preservation and restoration of listed (rare and protected) plant species in the upper Midwest and all of the native Minnesota orchids,” Weise says. “My work takes me to places all over Minnesota and the upper Midwest to survey for specific plants, collect samples (root fragments in the case of orchids) and seeds that go into our long-term seedbank. It’s exciting, rewarding, and challenging work.”

Weise, who has worked in the field of plant conservation since 2006, loves exploring the diversity of plants, animals, insects and fungi she encounters through her work. “I love that I experience places off trail, and that I am able to spend time in areas where often the only sounds of nature,” she says.

While Weise was specially qualified to detect the Japanase stiltgrass because of her background in botany and experience working in areas where the grass was common, anyone with a passion for plants can report invasive species to the EDDMapS website. “This online database and mapping tool alerts professional to new species and can allow groups like a Department of Natural Resources to take action and manage these sites before they spread,” Weise says.

If you’re interested in learning more about invasive species, Weise also recommends checking out the Minnesota Wildflowers website and app, Midwest Invasive Plant Network and Minnesota Department of Natural Resources.

For general learning about nature and the environment, Weise recommends exploring the Minnesota Master Naturalist Program. They are offering online courses during the pandemic. (Minnesota Master Naturalists also contribute their observations of plants and animals at the Arboretum to this blog each Monday.)

There’s another easy thing hikers can do to stop the spread of invasive species: Clean your boots between hikes. Seeds from invasive plants can unwittingly be spread by muddy boots.

4 comments on “Invasive Discovery: Japanese Stiltgrass

  1. I don’t understand wearing a mask working with the plants❓ If using ’round-up’ to rid poison ivy you should wear a respirator ‘gas’ mask 😉

  2. Pingback: Arb Links, Vol. 26 | News from the Minnesota Landscape Arboretum

Comments are closed.

%d bloggers like this: