Tallgrass Prairie Center

Managing county roadsides

Target sprayingIRVM was introduced to Iowa in the mid-1980s in response to the need for surface water protection. Prior to that time, roadside weed control relied on herbicides blanket-sprayed across the right-of-way. Besides being expensive and contributing to surface water pollution, blanket-spraying was ineffective. By weakening desirable vegetation and creating bare spots, weeds flourished.

The solution was an integrated approach to weed control using a variety of methods:

Strategic herbicide use
Replace blanket-spraying with spot-spraying, targeting undesirable species using the right herbicide at the right time.
Spot-mowing and prescribed fire   
Properly timed, these weed control methods are effective.
Native vegetation establishment
Naturally adapted to tough roadside conditions, healthy stands of tall, deep-rooted native plants outcompete weeds.

The integrated approach to roadside maintenance now extends beyond weed control to erosion control, brush control and stormwater management – all relying, when practical, on the use of native vegetation.

The Benefits of Native Vegetation in Iowa Roadsides

  • Native plants are durable, long-lived perennials well-adapted to Iowa’s climate and growing season.
  • A diverse native planting adapts to a wide range of soil and moisture conditions.
  • Extensive, native plant root systems provide superior erosion control.  See our Prairie Roots Project for more.
  • Deep roots and dense, above-ground foliage reduce stormwater runoff by intercepting raindrops, slowing water flow and increasing infiltration.
  • Extensive roots and decaying foliage further increase stormwater infiltration by adding organic matter to the soil, making it spongier and more absorbent.  
  • Extensive root systems penetrate 6-8 ft. or deeper, enabling prairie plants to survive drought and high salt concentrations while depriving weed roots of water, nutrients and space.
  • Tall prairie vegetation shades out Canada thistle and other weed seedlings.
  • A wide swath of prairie grass in the right-of-way traps blowing snow.
  • Native roadside plantings provide valuable habitat for songbirds, game birds, small mammals and pollinators.
  • Native plants beautify the right-of-way in a manner that reflects Iowa’s historic prairie landscape.

Roadside monarch