Weed Control


The Anaconda-Deer Lodge County Weed Control Department protects and preserves the agricultural, recreational, and natural areas of the County from the degrading impact of exotic, invasive, and noxious weeds. 

Noxious Weeds

A noxious weed is defined as “any exotic plant species that may render land unfit for agriculture, forestry, livestock, wildlife or other beneficial uses, or that may harm native plant communities.”


The Weed Control Department achieves its mission by doing the following:

  • Assisting landowners with sprayer calibration and herbicide information
  • Completing all state required reports
  • Coordinating spraying between County, State, Federal and private landowners
  • Distributing of biological control agents
  • Enforcing State Weed Laws
  • Inspecting noxious weed seed free forage
  • Inspecting subdivisions
  • Issuing non compliance letters
  • Ordering herbicides
  • Writing and administering weed grants
  • Writing and updating the County Noxious Weed Plan

County Weed Management Plan

Before construction or disturbance begins, please complete and submit a copy of the Noxious Weed Management and Revegetation Plan (PDF) to the Anaconda-Deer Lodge County Weed Control Office for review by the Board.

Montana War on Weeds Project

The Montana War on Weeds Project has an online, noxious weeds in Montana identification tool and provides further education of noxious weed prevention.

Spray Calibration

Proper sprayer calibration is an extremely important step in the application of herbicides. Often, sprayers are not calibrated properly, which results in poor weed control from under application or crop damage from over application.

In order to determine the proper amount of chemicals to add to a spray tank, the capacity of the spray tank must be established - i.e. one gallon versus 500 gallons.

The Sprayer Calibration document (PDF) provides step-by-step instructions to determine the number of acres the pesticide mix in a tank will spray.