Contact Information

Teton County Courthouse
150 Courthouse Drive - Room 107
Driggs, ID 83422

150 Courthouse Drive- Room 107
Driggs, ID 83422

208-821-0984 (phone)
208-776-8190 (fax)

Summer Office Hours: Mon-Thu 3:00 to 5:00 PM


What is a noxious weed?

Noxious is a legal designation. The State of Idaho designates exotic invasive plant species as noxious if they pose a serious threat to agriculture and/or the environment. Landowners are required to control noxious weeds on their property. Idaho has both terrestrial and aquatic noxious species.

Are all weeds noxious?

No. Some exotic species are not invasive. Some exotic invasive species have not been listed- usually these do not compete well in undisturbed areas or there is a lag is legislation.

How did weeds get here? 

Noxious weeds and other exotic invasive plants were introduced by humans either as crop seed contaminants, ornamentals that then escaped, or from dumping aquariums plants into streams. Most problematic species are introduced from climatically similar regions in Eurasia.

How can plants be "bad"?

Exotic invasive weeds evolved in their home range with viruses, fungi, mites, insects, and other plants that kept their population in balance. Most of these species have evolved to exploit disturbance. In their introduced range, they do not have their predators and pathogens to keep them balanced. This allows them to displace natives in disturbed sites like roadsides, overgrazed pastures, and burned areas.

Why do noxious weeds matter?

  • Species like Yellow Starthistle can displace native species, form monocultures and reduce biodiversity. This can ripple up the food chain.
  • Many species are toxic or unpalatable to wildlife and livestock.
  • Species like Knapweed can alter soil chemistry to make it more difficult for natives to grow. Others increase erosion.
  • Cheatgrass alters fire frequencies- shortening a native ecosystem's 25+ year cycle fire every 5 years or so.
  • Aquatic weeds form dense mats in waterways. This makes it impossible for boats and promotes fish like pike and bass over native trout that require open water. 

 What can I do to prevent the spread of noxious weeds?

  • Play, Clean, Go- Clean ATVs, bicycles, shoes and other gear after recreating to avoid transporting seeds site to site.
  • Clean, Drain, Dry- Make sure boats and waders are dry and free from plant debris to avoid transporting species between water bodies.
  • Use certified weed free gravel, hay, mulch and potting soil.
  • Maintain healthy competitive vegetation on your property so weeds can't take hold.

How can I control noxious weeds?

Contact Teton County Weeds for site and species specific recommendations. 

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