A joint project led by Illinois Department of Transportation Roadside Maintenance Manager Scott Hall with the Illinois Center for Transportation at the University of Illinois Urbana-Champaign is evaluating the use of native plant species along state roadsides, according to a March 30 announcement.
The initiative seeks to determine which native species can thrive on Illinois roadsides and what benefits they may provide. The study is significant because using native vegetation could help stabilize soil, reduce erosion, improve water quality, and create habitats for pollinators while potentially lowering maintenance costs.
Hall said, “The use of native vegetation along roadsides is important because native vegetation is a sustainable, low-maintenance solution that helps to stabilize soil and reduces erosion, helps to filter runoff and improve water quality, and provides crucial habitat for pollinators. This vegetation helps to reduce maintenance costs, herbicide use, creates natural beauty, and can act as safety barriers by reducing snow drifts. This study identified the most suitable native vegetation to utilize on Illinois roadsides as well as reexamine the types of vegetation we currently have in our standard seed mixes.”
Historically, IDOT has planted mostly non-native species due to limited research about which natives would succeed. UI Professor Jeffrey Matthews said, “The goal with roadside planting is not necessarily to restore a native prairie, but to plant native species that provide certain benefits that the native species provide. The rationale behind our work was to determine which [native] species are more or less appropriate for planting on roadsides.”
Researchers examined 34 existing roadside plantings in Illinois and Indiana to assess present species and factors influencing their success such as distance from roadways or soil conditions. They also tested new seed mixes designed by UI Graduate Research Assistant Wesley Bollinger at four IDOT locations alongside current mixes.
Results showed that coverage of natives increased farther from roadways but declined where soil nitrate and phosphorus were higher. Overall findings indicate using natives can be cost-effective if properly maintained. Bollinger said, “There’s a lot of good for the environment to be done with this, but also a lot of good from a dollars and cents perspective within the DOTs themselves. There’s plenty of evidence to suggest that native species can do well in these areas.”
