IRVM: Noxious 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 Perennial Sow thistle Poison Hemlock
Bull Thistle Quackgrass Puncture Vine
Canada Thistle Russian Knapweed Red Sorrell
Field Bindweed Tall Thistle Smooth Dock
Hoary Cress Buckhorn Plantain Teasel
Horsenettle Cockleburs Velvetleaf
Leafy Spurge Wild Sunflower Wild Carrot
Musk Thistle Curly Dock Wild Mustard
Multiflora Rose Shattercane Purple Loostrife

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.