A century has passed after a company in Knoxville, Tennessee received a shipment that contained packing materials. It did not take long before bushy Japanese Stiltgrass that cushioned the goods started to grow along a nearby stream bank and began to spread all over the country.
To see the results of that long-ago event, area residents need travel no further than Southern Illinois’ majestic Shawnee National Forest, where Japanese Stiltgrass has taken up residence with a vengeance. The invasive plant carpets acres of the forest, crowding out other native plants, changing soil conditions and worsening fire hazards during dry years.
Researchers at Southern Illinois University Carbondale have been working on the issue for years and played host to a summit that featured their colleagues from around the country.
The results of the summit, in August 2010, are now contained in a recently Internet-published white paper paid for by a grant from the Illinois Department of Natural Resources. The paper summarizes the many presentations, discussions and research presented at the summit and will serve as a valuable resource for land managers struggling to stem the Japanese Stiltgrass tide.
David Gibson, professor of plant biology at SIU Carbondale, said the University worked with the River to River Cooperative Weed Management Area to organize the summit. The CWMA works in counties south of Interstate 64 to combat invasive plants and educate the public on the threat they pose.
About 75 people, including representatives from the U.S. Forest Service, the state Department of Natural Resources and other agencies, attended the two-day event, which included presentations and field trips, Gibson said. Then recently, doctoral student Karla L. Gage reviewed the taped presentations and images and put together the summary.
Japanese Stiltgrass first was discovered in the United States in 1919 as it grew along a streambed near a warehouse in Knoxville.
“People figured it had been used as a packing material, like straw,” said Gage, a doctoral student in plant ecology from Selmer, Tenn., who summarized the summit and wrote the paper.
One thing for sure, however, is that once it gets somewhere, it’s hard to get rid of. The plant creates numerous tiny and sticky seeds, both in flowers and inside its branches, ensuring that the seeds not only spread by dispersing but also end up in the soil. Once in the soil, the seeds last about five years.
“So even if you go and clear out the plant one year it will keep coming back for several years after,” Gibson said.
The plant crowds out native species and there is some evidence that chemicals secreted by its roots negatively affect the nutrient cycle and the ability for other seeds to germinate, possibly hurting forest regeneration following fire events.
“It can climb trees,” Gibson said. “The problem is that, although fire is generally a good thing in forest, when this plant dries out during the winter season it can provide a fire ladder leading up into the trees, where it can lead to crown fires.”
“The University provided a great venue and staff support for the Stiltgrass Summit. Also, the Department of Plant Biology and Center for Ecology both participated by sponsoring and helping plan the summit,” Evans said.
Evans said the white paper would be an important tool for land managers who battle the Japanese Stiltgrass problem throughout the area.