Teton County Weed and Pest Control Priorities

Last Updated January 30, 2008

The following list has been prepared by Teton County Weed and Pest, to be used as a guide outlining the noxious weed priorities for Teton County. The noxious weed priorities of our federal and state partners may vary.

Private landowners are encouraged to contact TCWP for a free consultation to establish management objectives appropriate for localized areas.

All of the following weeds may move to a higher priority if found in areas that are currently non-infested.

Priority 1: No tolerance, with a goal of eradication upon detection

Weeds in this category are considered by Teton County Weed & Pest to be highly invasive, pose the highest threat to native plant communities, are known to render land unfit for wildlife and livestock grazing, reduce land value and recreation, and are found or were previously found in extremely low numbers in Teton County. Early detection and rapid response along with noxious weed education will be used with a goal to eradicate these weeds.

1. Purple loosestrife (Lythrum salicaria)
2. Leafy spurge (Euphorbia esula)
3. Yellow starthistle (Centaurea solstitialis)
4. Perennial pepperweed (Lepidium latifolium)
5. Rush skeletonweed (Chondrilla juncea)
6. Saltcedar (Tamarix spp.)
7. Common teasel (Dipsacus fullonum)
8. Meadow knapweed (Centaurea pratensis)
9. Plumeless thistle (Carduus acanthoides)
10. Scotch thistle (Onopordum acanthium)
    
11. Squarrose knapweed (Centaurea virgata)
12. Myrtle spurge (Euphorbia myrsinites)
13. Cypress spurge (Euphorbia cyparissias)
14. Orange hawkweed (Heiracium aurantiacum)
15. Yellow hawkweed (Heiracium pretense)
16. Dyer’s woad (Isatis tinctoria)
17. Russian knapweed (Centaurea repens)
    
18. Diffuse knapweed (Centaurea diffusa)

Priority 2: No Tolerance, aggressive control on all known infestations

Weeds in this category are considered by Teton County Weed & Pest to be highly invasive, pose a high threat to native plant communities, are known to render land unfit for wildlife and livestock grazing, reduce land value and recreation, and are found in low numbers in Teton County. Containment and reduction of current infestations, early detection and rapid response of new infestations, use of biological control measures, along with noxious weed education will be used to control, reduce numbers, and in certain circumstances eradicate.

1. St. Johnswort (Hypericum perforatum)
2. Field scabious (Knautia arvensis)
3. Field bindweed (Convolvulus arvensis)
4. White top (Cardaria draba and Cardaria pubescens)
5. Common burdock (Arctium minus)
6. Sulfur cinquefoil (Potentilla recta)
7. Skeletonleaf bursage (Franseria discolor) (No known infestation and a native to the plains, but is on the state designated noxious list)
8. Russian Olive (Elaeagnus angustifolia) (excluding established trees on private locations)
9. Absinth wormwood (Artemisia absinthium)

Priority 3: No tolerance of further spread from their established locations, control and maintenance of current weed infestations and aggressive control to areas otherwise free of these weeds.

Weeds in this category are established in large numbers in localized areas only. They are highly invasive, their further spread poses a significant threat to non-infested native plant communities, and they currently render land unfit for wildlife and livestock grazing, and reduce land value and recreation. Containment of current infestations through the use of best management practices and biological control, stopping further spread through early detection and rapid response of known non-infested areas along with noxious weed education will be used to maintain, control, and reduce weed numbers.

1. Common tansy (Tanacetum vulgare)
2. Oxeye daisy (Chrysanthemum leucanthemum)
3. Spotted knapweed (Centaurea maculosa)
4. Dalmatian toadflax (Linaria dalmatica)
5. Yellow toadflax (Linaria vulgaris)
6. Hoary alyssum (Berteroa incana)
7. Black henbane (Hyposcyamus niger)
8. Houndstongue (Cynoglossum officinale)
9. Scentless Chamomile (Tripleurospermum perforata)

Priority 4: No tolerance of further spread, control and maintenance of current weed infestations.

Weeds in this category are established throughout Teton County in large numbers. They are highly invasive, their further spread poses a significant threat to non-infested native plant communities, and they currently render land unfit for wildlife and livestock grazing, and reduce land value and recreation. Containment of current infestations through the use of best management practices and biological control, stopping further spread through early detection and rapid response of known non-infested areas along with education will be used to maintain these weeds at there present level.

1. Canada thistle (Cirsium arvense)
2. Musk thistle (Carduus nutans)
3. Bull thistle (Cirsium vulgare)
4. Common mullein (Verbascum thapsus)
5. Perennial Sowthistle (Sonchus arvensis)
6. Quackgrass (Agropyron repens)

Weeds not currently known in Teton County and are not on the state designated or Teton County declared noxious weed list, but are considered by other states and other organizations to be highly invasive and pose a significant threat to native ecosystems of the west.

The Teton County Weed and Pest Considers These Weeds as Priority 1 if detected.

1. Japanese knotweed (Polygonum cuspidatum)
2. Hydrilla (Hydrilla verticillata)
3. Eurasian Watermilfoil (Myriophyllum spicatum)
4. Garlic mustard (Alliaria petiolata)
5. Tansy ragwort (Senecio jacobaea)
6. Common crupina (Crupina vulgaris)
7. Scotch broom (Cytisus scoparius)