ACRES Land Trust, with regional partners, is fighting to eradicate Japanese stiltgrass, a non-native invasive plant common to southern Indiana and the eastern United States and newly identified in northern Indiana in late fall, 2015.
Japanese stiltgrass can crowd out native plants, reducing tree regeneration and slowing the growth of tree seedlings and existing plants, creating a monoculture. It is an annual plant, spread by seed, often by foot. Japanese stiltgrass thrives in a variety of soil and light conditions.
Little Cedar Creek, which borders the preserve where the invasive was first found and the 100-acre area where the species has invaded, is a tributary of Cedar Creek. Cedar Creek is one of three rivers in the state designated under the 1973 Indiana Natural, Scenic and Recreational Rivers Act.
Ben Hess, then Regional Ecologist, Department of Natural Resources, Division of Nature Preserves, spotted the non-native plant during a routine assessment of the preserve. This plant was not on the watch list at the time, as it had never been seen before; it was growing in such abundance, it caught his attention.
Local partners in treating the outbreak and monitoring natural areas for the plant include The Nature Conservancy, Indiana DNR Division of Nature Preserves, Allen County Highway Department, Fort Wayne Parks, Fort Wayne Trails, and Little River Wetlands Project. The Indiana Native Plant and Wildflower Society (INPAWS) and the Olive B. Cole Foundation are funding partners.
ACRES has identified Japanese stiltgrass on other preserves in small patches, away from trails where the invasive does not pose as great of a threat of spreading by foot traffic — from seeds sticking in boot treads. These preserves will remain open to visitors, who must stay on the trails and keep dogs on leash to keep the seeds from invading other natural areas and their own property.
The nonprofit has seen success spraying large patches of the invasion with a grass-specific herbicide. For a season, it looked like victory was in sight; and then the organization saw new seedlings emerged from the soil bank.
The team has been persistent and creative in its attack.
“As a warm season grass,” said Jones, “Japanese stiltgrass will bolt when surrounding vegetation growth slows. So, we encourage it, letting it grow to about twelve inches and then mow it just before it goes to seed, preventing it from spreading. From there, we’ll watch for dormant seeds to emerge over the next few years.”
“We met with the Allen County Highway Department to coordinate our plan of attack with mowing and spraying,” said Casey Jones, director of land management for the local nonprofit land trust.
With the help of its summer land management interns, supported by the Olive B. Cole Foundation, ACRES has invested thousands of hours spraying the invasive plant. A private contractor is helping ACRES assess the impact Japanese stiltgrass has on local flora.
May to October, Japanese stiltgrass is identified by its broad, bright green leaves with a faint luminescent line down the mid-section, forming a shallow ‘v’ as they extend from the stem. If you see a suspected infestation take a picture of the grass and report it on-line through Report IN, an invasive plant reporting system at EDDMapS.org/Indiana.