Stiltgrass

Stiltgrass (Microstegium vimineum) is an annual, warm season grass that thrives in moist forests with partial shade, though it is also capable of invading open upland areas or heavily shaded sites.

 Plants are typically 1-6’ tall with short, wide leaves, and delicate, sprawling stems. Stiltgrass negatively impacts biodiversity by outcompeting native species and has also been shown to alter nutrient cycling and soil biota, and even change fire behavior.

Photo by Lynn Harper, iNat

Report stiltgrass using EDDMapS. Early detection is key to controlling new invasive species. We want to know if its in Minnesota and spreading. 

Watch this 2:11 minute video to learn how to report to EDDMapS.

Stiltgrass germinates early in spring, but puts on most of its growth in mid-summer, flowering and setting seed in late summer or early fall. In winter it leaves behind an abundance of straw-colored thatch which can be helpful for identification. It is a prolific seeder, producing 100-1,000 seeds per plant which can be spread by water flow, human and vehicle traffic, and by wildlife. However, only a small percentage of seeds survive in the soil for more than two years, so management efforts should focus on reducing seed production. Stiltgrass can also spread through a system of underground stems (stolons).

Stiltgrass can be distinguished from native look-alike grasses in the following ways: weakly rooted annual, aerial “stilted” roots, short (2-4”), wide 0.5-0.75” leaves that may have a white/silvery midvein and inflorescences have 1-3 branches.

Watch this 4:10 minutes stiltgrass video from Penn State University.