Mahaska County Courthouse

IRVM: Weeds

The state of Iowa lists the following weeds as noxious. They are to be treated and removed from all lands in Mahaska and every other Iowa county. They are as follows:

  • Buckthorn
  • Bull Thistle
  • Canada Thistle
  • Field Bindweed
  • Hoary Cress
  • Horsenettle
  • Leafy Spurge
  • Musk Thistle
  • Multiflora Rose
  • Perennial Sowthistle
  • Quackgrass
  • Russian Knapweed
  • Tall Thistle
  • Buckhorn Plantain
  • Cockleburs
  • Wild Sunflower
  • Curly Dock
  • Shattercane
  • Poison Hemlock
  • Puncture Vine
  • Red Sorrell
  • Smooth Dock
  • Teasel
  • Velvetleaf
  • Wild Carrot
  • Wild Mustard
  • Purple Loosestrife

Treatment of these species varies. Timing of herbicide applications is the most important part of getting a successful kill. The target plant has to be actively growing for most herbicides to work well.

The best ways to control weeds varies in opinion with each person you ask. However, this common sense approach has been what Mahaska County I.R.V.M. has held to in the past few years.

  1. Prevent Weeds
    Remember the old saying that, "an ounce of prevention is worth a ton of cure?" That applies to weed problems as well. If you create openings for weeds, they will take them. Overgrazing a pasture, mowing too short, scalping the ground with the mower, mixing herbicides outside of the label recommendations... these are all ways to weaken existing vegetation systems and allow openings for weeds to occur.
     
  2. Do Not Allow Bare Soil
    Nature does not allow bare soil to exist. It covers its wound with something and that something is usually a weed. Keep soil in the fields where it belongs, and out of roadsides. Less weeds result.
     
  3. Do Not Stop Weed Control
    Once you begin weed control, you can not stop until the weeds are all gone, and allow enough time to allow the seed in the seed bank to mature before considering an area clean. Remember, all it takes is a disturbance and you are right back to square one. Keep a watchful eye.