Noxious Weeds

Noxious Weeds

Euphorbia esula L. – Leafy Spurge

The Conservation District works in multiple arenas pertaining to noxious weed control.  

Centaurea diffusa – Diffuse Knapweed

The District has helped sponsor a Dearborn River Watershed Spray Day to assist private landowners in the area with the huge task of working on their weeds.

Centaurea solstitialis – Yellowstar Thistle


The District also contributes to the annual Weed Whacker Rodeo in the Sun River Canyon.  They have a weed pull and contests to see who pulls the most weeds and the biggest weeds. 

Lythrum salicaria – Purple-loosestrife


Pilosella aurantiaca – Orange Hawkweed

Most recently in 2011, the Board of Supervisors elected to use some of their extra funds in a Weed Cost Share program for county landowners. The 2011 program was a pilot program, and the 2012 program was opened up more widely and will continue until we no longer have funds to maintain the program.  

The Weed Cost Share program is a 50/50 match to cover chemical and surfactants, or the cost of a Commercial Weed Applicator.

In addition, the program can help with the cost of re-seeding, because removal of weeds only goes so far sometimes!

Leafy Spurge

Spotted Knapweed

Diffuse Knapweed







Also as part of the Weed Cost Share Program, we can assist landowners who purchase insects from a dispensary to reduce pest populations with the use of natural enemies by utilizing an integrated weed control method.

Biological control is combining pest management strategies.  When you have a pest such as invasive plant species, the goal is to remove those invasive plants while replacing them with good species. An alternative to chemical herbicides is the use of biological control. Biological Control is the release of a natural control (predators, parasitoids, and/or pathogens) of the invasive plant.  It is also vital to preserve existing natural enemies that do not harm beneficial species.  You want the natural control to have a high reproductive rate to decrease invasive populations quickly and then as the invasive host dies the population of the natural control will decrease.