Prairies to Preservation: IDOT Uses Emerging Landscape to its Advantage in Maintaining Roadside

That was until IDOT adopted mowing policies to protect the habitat and migratory patterns of the monarch butterfly, other insects, and species like ground nesting birds that use our rights-of-way as a food source. That policy mows the state’s roads in a four-year rotation during the summer, the least invasive time. Interstate medians are mowed one year, westbound and southbound interstate right-of-way is mowed the second year, eastbound and northbound interstate right-of-way are mowed the third year, and non-interstate routes like Illinois 54 are mowed the fourth year. In addition to mowing, the policies allow for site-specific targeted maintenance activities to aid in eradicating of invasive plants. Then the cycle starts over.

Stahr, Keigher and Rutledge decided to take it a step further by limiting the mowing width District 3 does in Ford County (with exceptions for vision clearance at intersections, railroad crossings, turnarounds and providing space for motorists to pull to the side for emergencies). Nature returned the favor with prairie plants creeping onto IDOT’s roadsides.

“We didn’t sow native seeds here,” Keigher says, pointing to new prairie growth in a cleared area outside Thawville. “These plants spread from the existing remnant prairie on the railroad property. This wouldn’t be here if it wasn’t for our new mowing policy. We would’ve mowed 30 feet wide through here and we used to do that.

“Since we stopped doing that, I’ve seen more and more plants like these moving up our slopes and onto our backslopes.”

Maintaining the Present. Building the Future

Great as it is to have the railroad’s prairie spread onto IDOT’s land, that doesn’t mean the job is done, Stahr says. While it means roadside mowing is kept to a minimum, work needs to be done in maintaining a prairie.

“It’s going to be a constant problem because you have weeds coming in every direction,” he says. “You’re always going to have spots where Canada thistle pops up. That’s why you can’t completely step away from it. Every once in awhile you’re going to see a patch of something and you’re going to have to go in and herbicide it out and you got to reseed that little patch.”

Keigher says a lack of maintenance threatens that effort. Pointing to a large invasive Russian olive tree in the distance, he says it will block the sun and kill existing plants if left unchecked. The tree also can attract birds that transport invasive seeds through their excrement and recontaminate the prairie.

The solution? Mow it down to the ground and kill it.

“You can’t just quit,” Keigher says. “You have to keep maintaining that.”

Across Illinois 54 is a roadside prairie that matches the one near the railroad. Unlike the railroad prairie, this one was reconstructed — a process that is as involved as it sounds.

“There’s a lot of steps involved, and it’s about a three- to five-year process before it starts to get to a point when it’s fairly self-maintained,” Stahr says.

Reconstruction means applying herbicide to kill all existing vegetation at the site and scarifying the soil. Then it’s managing the land for up to two years by mowing. Seed also are drilled into the ground to establish a deep root system.

“Once it’s seeded, we really don’t have to do anything else to make it grow other than keep the vegetation and weeds down for that first year,” Stahr says. “You may be able to let it go the second year if you get a great response. It’s usually the third year that you can let it go and you’ll see everything start to bloom.”

Done right, the prairie polices itself against invasive plants.

“There’s only so much space in the root system” Stahr says. “Once you get all these plants living together in such density like this, they interlock their root systems so aggressively that when a weed seed lands in here, there’s nowhere to germinate and grow. That’s why they’re so low maintenance when you get them established.”

Picking Spots

In addition to the tracts outside of Thawville, Illinois 54 features several other reconstructed tracts heading south to Roberts. Although signs note IDOT crews and nearby property owners not to cut, the three acknowledge they have work to do in educating others about what they’re doing.

In some instances, it’s Keigher making sure his staff don’t cut deep into the prairie. It’s also convincing farmers who have land adjacent to IDOT property to respect its plans. For this stretch of Illinois 54, Keigher enlisted Pheasants Forever, who donated seed and partnered with IDOT in Operation Habitat, were critical in spreading the message to farmers and getting their buy-in for preserving habitats on their properties.

“Sometimes farmers like to mow next to their crops to show the edge, especially if they’re cash renting. It shows they’re on top of maintenance,” Keigher says. “I understand they have a business to run, and they have to do what they have to do, but I hope they don’t cut too wide.”

Keigher is always on the lookout for unmowed ditches of right-of-way along railroads that have the start of prairie spread onto it. When he sees it, he stakes his claim with a prairie plant sign.

While Keigher would love to see every roadside receive this treatment, he prefers to do smaller quarter-mile prairie sections at a time.

“We’re expanding at the rate where we can maintain it,” Keigher said. “We just can’t do it all because we don’t have enough time to take care of it. It’s a lot. We wanted to make sure we’re successful at it before we bite more than we can chew.”