7/21/2025 McCall Macomber
Written by McCall Macomber
Roadways serve as more than just a way to move people and goods — they also hold the potential to host native plant species, providing environmental and economic benefits.
Illinois Center for Transportation and Illinois Department of Transportation evaluate the use of native species on Illinois roadsides in a joint project, “R27-255: Illinois Department of Transportation’s Seeding Standards and Best Management Practices.”
Jeffrey Matthews and Rabin Bhattarai, University of Illinois Urbana-Champaign professors, led the project with Scott Hall, IDOT’s district 5 roadside manager, and Wesley Bollinger, Illinois graduate research assistant.
Effectively planting native species on roadsides will improve habitat for pollinators, increase soil stability, and reduce fuel and maintenance costs needed to manage rights-of-way.
Using native species comes with challenges, however, as IDOT has historically planted mostly non-native species on roadsides, and little research has been conducted on which native species will grow and thrive there.
“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,” Matthews said. “The rationale behind our work was to determine which [native] species are more or less appropriate for planting on roadsides.”
The researchers examined 34 existing roadside plantings in Illinois and Indiana to see what native species were present, learn how they were maintained and determine factors that may have led to their long-term success.
Factors that may contribute to successful planting include distance from the road, soil compaction, surrounding land uses and soil conditions, among others.
They also designed and planted native mixes at four IDOT locations, doing a side-by-side comparison of existing IDOT seed mixes to their newly designed ones.
Newly developed designs with native species, created by Bollinger, include those for use in roadsides, lawns and sloped areas.
They found that coverage of native species tended to increase farther from the road but decreased in areas with higher levels of soil nitrate and phosphorus.
Their results after planting showed that using native species on roadsides in Illinois is a viable, cost-effective practice, provided they are maintained correctly.
“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,” Bollinger said.
“There’s plenty of evidence to suggest that native species can do well in these areas,” he added. “The larger challenge is going to be the adoption of these changes.”
The researchers provided IDOT with a list of successful native species by mix type as well as policy recommendations, with hopes of increasing IDOT training practices across districts related to native seeding and boosting success rates.
“Hopefully our study will not only spur some changes IDOT-wide, but also generate some interest at the district level in establishing and maintaining native plantings,” Matthews said.
Editor’s note:
Questions about the research may be directed to Wesley Bollinger at wesleyb3@illinois.edu.