Roadside Maintenance

Roadside maintenance is important at IDOT. We ensure that our roadsides and right-of-ways are maintained and cleared of debris, and we take a special interest in preserving the native wild prairie lands. Below, you can find prairie inventory reports and information on how to protect our wild prairies from invasive species.

Invasive Species
Prairie Inventory

Invasive Species

Teasel: Teasel is an aggressive monocarpic biennial invasive species known to create a monoculture which smothers out desirable native vegetation and roadside grasses. Teasel is not controlled by mowing. Mowing can actually cause this plant to live more than 2 years. Allowed to flower, each plant is capable of producing 6,000 seeds. Mowing the teasel after it has flowered can cause the seeds to be dispersed over a greater area.

While thousands of dollars are spent each year targeting weed species on Illinois’ highways, this plant continues its spread due to the lack of knowledge needed to reduce its spread and the means by which it is unknowingly spread. To learn more about the teasel growth cycle click here.

Prairie Inventory

Illinois, “the prairie state,” once contained an estimated 22,000,000 acres of its dominant plant community type, native prairie. After the invention of the self-scouring steel plow in 1837, the rich prairie soils quickly were converted into some of the most fertile cropland in the world. By 1976 it was estimated that only 2,352 acres of high-quality native prairie remained in Illinois, about 1/100th of 1 percent of the original acreage. Much of that prairie occurs along Illinois’ roadsides between roadways and railroads, due to protection from cultivation and other disturbances. Prairie communities are of special concern in Illinois because of their rarity, species diversity, and vulnerability to habitat degradation. At the direction of IDOT’s Bureau of Design and Environment, an inventory of native Illinois roadside prairie remnants was conducted by botanists from the Illinois Natural History Survey during the field seasons of 2001-2003. The area surveyed occurred where roadways and railroad lines (both active and abandoned railroads) occurred within four hundred feet of each other. Results of the inventory are found below in the form of maps and text. The type of information collected for each site included its location, quality, size, distance from edge of pavement, and species list.

Instructions for Use

Find the county of interest in the list below. Click on the corresponding District to view the appropriate map and report. (*Note – These maps and reports were created prior to IDOT’s re-districting) First open the map and record the number adjacent to any of the identified prairie remnants. Then open the corresponding report to find specific information associated with that remnant. GIS data is also available at the bottom of this page.