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West: Controlling weeds on your grazing lands

Meranda Small for Progressive Cattle Published on 23 April 2021

Pairs are venturing out for summer grazing, so for many in the West it’s time to put on the farming hat and complete some grazing land management practices.

When it comes to good pasture and grassland management, one needs to be aware and proactive, preparing for and reacting to current conditions. This would include making the most of grasslands and maximizing grass production with continued monitoring and management practices.

Why is controlling the presence of noxious, invasive weeds necessary? Weeds will compete with preferred grasses. We define a weed as any plant growing where it is not wanted – that can be native or foreign, invasive or non-invasive, noxious or not. By legal definition, a weed is any plant that grows out of place and is competitive, persistent and harmful. Be aware, though, that invasive is not necessarily the same as noxious; however, many noxious weeds are invasive. Foreign plants are typically invasive, as they’ve evolved in a different environment, resulting in no natural limits to their spread. Noxious plant invasions occur with overgrazing, after a fire, through seed dispersal by animals, with climatic fluctuation, after soil disturbance and as a consequence of erosion.

Prevention and control of weeds is based off good management, which means having a good grass stand and soil health, re-seeding preferred forages, appropriate herbicide usage, reduction of fire fuel and, if applicable, potentially applying fertilizer. It would also be good practice to employ rotational grazing. You could also use mob grazing, meaning aggressive grazing, if needed for controlling certain weeds. Be careful to not overgraze.

These are practices that can be implemented on private land. So what about public lands? The USDA works with private landowners in joint control efforts. The Forest Service as well as the Bureau of Land Management operate weed control crews to spray for noxious weeds during the summer season. They accomplish this by relying on land users’ input and notification of new infestations. At times, the Forest Service has utilized bio-control agents in remote areas. At the county level, there may be the option of working with Cooperative Weed Management Areas and the county weed departments.

Weeds of major concern include poison hemlock, yellow star thistle, houndstongue, dyer’s woad and spotted knapweed. Weeds of less concern include curly dock, whitetop, leafy spurge, and scotch and musk thistles.

Weeds of major concern are toxic, already present in the area, very aggressive and hard to eradicate, whereas weeds of minor concern can be all those things but to a lesser extent. A valuable source for more in-depth information on these weeds as well as recommendations for managing them would be the Pacific Northwest Weed Control Handbook, which is updated annually. end mark

Meranda Small
  • Meranda Small

  • Extension Educator
  • University of Idaho
  • Email Meranda Small