Final Environmental Impact Statement - Appendices 

Wasatch-Cache National Forest H - 1 

APPENDIX H

Noxious Weeds of the Wasatch-Cache National Forest

This appendix discusses the known locations of various noxious weeds (Utah and/or 

Wyoming) that are known to occur on the Wasatch-Cache National Forest. Other species 

may occur, but those listed in Table H-1 have been identified on the Forest and are 

discussed in greater detail below. Included are comments on a few other species that are 

not classified as noxious weeds by either one or both of the states, but that are of concern 

because of their status in adjacent States, potential to become state noxious weeds, or 

because of their poisonous or injurious characteristics. Table H-1 lists noxious weeds 

and their occurrence within the ecological subsections of the forest. Sections that follow 

discuss these noxious weeds by Management Areas.

Table H-1. Noxious weeds that are known to occur in the three ecological sections of 

the Wasatch-Cache National Forest (unless noted, all plants are both Utah and 

Wyoming Noxious Weeds) 

Common Name Scientific Name 

Wasatch & 

Bear River 

Ranges 

Stansbury 

Mountains 

Uinta 

Mountains 

Canada thistle Circium arvense X X 

Common burdock1 Arctium minus X 

Dalmatian toadflax1 Linaria dalmatica X 

Dyers woad Isatis tinctora X X 

Field bindweed, 

morning glory Convolvulus arvensis X 

Houndstongue1 Cyonoglossum officinale X 

Knapweed, Diffuse Centaurea diffusa X 

Knapweed, Russian Centaurea repens X 

Knapweed, Spotted Centaurea maculosa X X 

Leafy spurge Euphorbia esula X 

Medusahead2 Taeniatherum caput-medusae X 

Musk thistle Carduus nutans X X 

Salt Cedar1 Tamarix spp. X 

Scotch thistle Onopordum acanthium X 

Whitetop Cardaria draba X X X 

Yellow starthistle2 Centaurea solstitalis X 

 

1

 Wyoming State Noxious Weed only 

2

 Utah State Noxious Weed only 
Final Environmental Impact Statement - Appendices 

Wasatch-Cache National Forest H - 2 

Noxious Weed Assessment by Management Area

Cache-Box Elder Management Area 

This management area likely has the greatest variety and concentration of noxious weeds 

on the forest. The most common noxious weed in this management area is dyers woad. 

While most abundant along roadsides and travel ways, it extends away from these areas 

onto adjacent areas. It occurs at nearly all elevations in the Bear River Range and has 

been noted at the lower to mid elevations of the Wellsville Range. Estimated population 

sizes range from less than 0.1 acre to over 200 acres in Wellsville Canyon and over 650 

acres in lower Logan Canyon. Leafy spurge has been found in both the Bear River and 

Wellsville Ranges. It has been inventoried in the Mount Naomi Wilderness and adjacent 

areas along South Canyon, High Creek, Cherry Creek and its tributaries, and City Creek. 

Leafy spurge occurs along the eastern slope on the Wellsville Range on Maple Bench 

and Coldwater Canyon, north to Three Mile Canyon. Musk thistle has been noted at two 

locations in Logan Canyon, near Wood Camp and along Bear Hollow. In addition, it has 

been found on the eastern portion of this management area and in the Bear Management 

Area at five locations within the North Rich cattle allotment. Canada thistle occurs 

primarily along streams throughout the management area, but mostly in the Bear River 

Range. Hemlock has been noted in Left Hand Fork Blacksmith Fork, Providence 

Canyon, Right Hand Fork, Franklin Basin, and Spawn Creek. Dalmatian toadflax has 

been noted in Cowley Canyon south of the Logan Canyon Highway. Russian 

Knapweed has been located in Logan Canyon near Beaver Mountain and spotted 

knapweed has been found in Mill Hollow. Black Henbane has been noted near Temple 

Fork and Saddle Creek Narrows. 

Bear Management Area 

Rich County to the east of this management area has a high concentration of noxious 

weeds and influences the occurrences of these species on the forest. The most commonly 

found weeds in Rich County, both on and off the Forest, include houndstongue, black 

henbane, Canada thistle, and musk thistle (Dewey 2000). Of the species found within the 

Bear Management Area, Canada thistle and houndstongue were the most common 

occurrences. Musk thistle while not as abundant was also present as were dyers woad, 

poison hemlock, hoary cress, and black henbane. 

North Wasatch-Ogden Valley Management Area 

Dyers woad is abundant on lands adjacent to the forest and is spreading onto the forest 

primarily along travel ways. Whitetop has been noted in lower Farmington Canyon, but 

likely occurs elsewhere. Spotted knapweed has been noted in Weber Canyon. It is not 

clear whether this population is on National Forest lands or on adjacent private lands, but 

it would be the highest priority for treatment. 
Final Environmental Impact Statement - Appendices 

Wasatch-Cache National Forest H - 3 

Central Wasatch Management Area 

Dyers woad is abundant on the lower elevations in this management area and is 

spreading up canyon travel ways. Whitetop has been noted in Red Butte Canyon. 

Dalmatian toadflax is abundant along the foothills and along travel ways in the canyons 

on the western portion of this management area, but has also been found at a site in Little 

Cottonwood Canyon on soils brought in for restoration work. In addition, wand mullein, 

which is not currently a Utah noxious weed, but which has the potential to be very 

invasive, has been found on this site. Jointed goatgrass has been noted in the drainage 

ditches along the lower portion of Big Cottonwood Canyon. More noxious weeds occur 

in this management area, but have not been inventoried by the forest. 

Stansbury Management Area 

Whitetop has been noted along many drainages in the Stansbury Mountains including, 

but not limited to North Willow, South Willow, Big Hollow, Barlow, Spring Creek, 

Round, Big Granite, Monument, and Chokecherry Canyons. Other species are likely to 

occur, but have not been inventoried. 

Western Uintas Management Area 

Dyers woad is beginning to expand into this management area from adjacent Utah. 

While it has only been noted at one location along Beaver Creek east of Kamas, it is on 

several sites south of Evanston where it has been identified near Carrot Hollow, Moffit 

East Fork, near Stillwater Campground and near the Bear River. White top has been 

noted in many of the same areas as well. Canada thistle is common throughout this 

management area, while musk thistle has been noted in Rileys Canyon, SmithMorehouse, Nobletts, Swifts, and Left Hand Canyon as well as scattered locations on the 

north slope of the Uinta Mountains in this management area. 

Eastern Uintas Management Area 

Canada and musk thistle are common throughout this management area. In addition, 

dyers woad has been found near the East Fork Smiths Fork and Little Dry Creek. 

Whitetop has been noted near Henrys Fork and spotted knapweed has been found near 

the forest boundary south of Mountain View. 

Source of Data: 

Data were from field observations and maps produced in 1999 from Range Management 

Specialists across the forest. In addition, GIS map layers provided by Dr. Steven Dewey, 

Professor at Utah State University provided information, both on and off the Forest, for 

areas in Box Elder, Rich, and Cache Counties (Dewey 1997, Dewey 1999, and Dewey 

2000).