Curious Iowa: Why can’t Iowans mow roadsides before July 15?

Mary Aschenbrenner, of Tama County, noticed ditches mowed and hayed in the summer while driving on Iowa Highway 21. Aschenbrenner wondered whether a permit and fee is required to harvest hay. “It certainly makes the roadway neat! And makes good feed for some farmer’s livestock,” Aschenbrenner wrote to Curious Iowa, a Gazette series that answers readers’ questions about our state and how it works.

Mowing the roadside vegetation on the rights of way or medians on Iowa highways, interstates or secondary roads before July 15 is prohibited, per Iowa Code 314.17.

The Gazette spoke with experts from the Iowa Department of Natural Resources and the Linn County Secondary Roadside Department about why this law is in place, and to find the answers to Aschenbrenner’s question.

Why is Iowa’s mowing law in place?

Iowa’s roadsides provide habitat and shelter for rabbits, pheasants, quail and other ground-nesting birds, and Iowa’s mowing law aims to protect this habitat during critical periods for young rabbits and hatchlings.

When Iowa’s mowing law went into effect more than 20 years ago, it prohibited the mowing of roadside vegetation prior to July 1. In 2010, the law was amended, changing the date to July 15.

According to the Iowa Department of Natural Resources, the two factors that determine both the abundance and distribution of Iowa’s upland game populations are weather and habitat.

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“We had some really bad winters and springs right around 2007 to 2010 ... (Due to) the decline that we saw because of those bad weather years with the quail and rabbits and other species, (the Legislature) pushed back to July 15 just to help those populations recover,” Todd Bogenschutz, upland game biologist with the Iowa DNR’s Wildlife Bureau, said.

This change provided ground-nesting birds with another two weeks of hatching and development in their roadside habitat.

According to previous reporting from The Gazette, 39 percent of pheasants’ nests are unhatched by July 1 and are likely destroyed with a July 1 mowing. Delaying mowing by two weeks allows an additional 17 percent of pheasant nests to hatch.

Bogenschutz said that the most critical period for nesting and brood rearing is between April through the end of September.

“But within that period, there’s kind of a critical period, which we usually say is between about early April through mid-July,” Bogenschutz said. “That’s kind of when the peak of nesting and the rearing of young occurs.”

By mid-July, when roadsides are allowed to be mowed, there are still birds in nests that haven’t hatched yet.

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“For pheasants, on average, there’s probably 20 percent in nests that haven’t hatched yet. If you go to like quail and songbirds, it may be 40 or 50 percent hatch after July 15, but certainly, a big portion of the nests have hatched,” Bogenschutz said.

Bogenschutz noted that the guidance given to participants in the Iowa Conservation Reserve Program is to mow after Aug. 1.

The 2024 August Roadside Survey Report, which surveys ring-necked pheasants, bobwhite quail, gray partridge, cottontail rabbits and white-tailed jackrabbits on approximately 225 30-mile routes, showed a decline in pheasant numbers compared to the year before. The 2024 roadside counts were comparable to the counts in 2021 and 2022.

The Iowa DNR also reported that 591,000 pheasants were harvested in 2023, marking the best pheasant hunting season in the state since 2007.

Bogenschutz said that the change from July 1 to July 15 is a trade-off.

“The landowners that would like to hay the ditch are usually doing it for forage ... so they would like to cut it earlier because then you get better quality forage,” he said. “The July 15 date is kind of (a) compromise.”

If landowners want to hay the ditch for forage, they need to obtain a no-cost permit.

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Driving through the state of Iowa in the summer, you’ll see streaks of color from plants like butterfly milkweed, blazing star, purple coneflower and goldenrod. The Iowa DOT uses Integrated Roadside Vegetation Management (IRVM), which includes planting flowers and grasses native to Iowa in the right of way.

These plants are a vital food source and habitat for pollinators.

Megan Huck, roadside manager for the Linn County secondary roadside department, said that native plants are planted wherever ditch work has been recently completed throughout the county. The department’s native seed mix comes from the Tallgrass Prairie Center and last year they received 90 acres of seed since they have an IRVM plan on file with the Iowa DOT. As of today, all of the seed has been planted throughout the county, Huck said.

What are the exceptions to Iowa’s mowing law? How is it enforced?

There are exceptions to Iowa’s mowing restrictions. For example, one can mow prior to July 15 within two hundred yards of an inhabited dwelling; for visibility or safety reasons; or for pest and weed control.

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While mowing before July 15 would violate Iowa’s mowing law, it’s rarely enforced. It can be difficult to track down who mowed an area early, and beyond that, one needs to determine whose road and jurisdiction the mowed area is in.

Both Huck and Bogenschutz said that fines are not issued for early roadside mowing.

“A lot of folks give us a call when they see ditches mowed before the 15th and all I can tell them is ‘Well, it’s not really our jurisdiction’,” Bogenschutz said.

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Comments: bailey.cichon@thegazette.com

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