Noxious and invasive weeds are plants considered harmful to livestock, agriculture, and wildlife, or otherwise negatively impact the landscape by (e.g., increase wildfire threat, reduced biodiversity). They are typically (but not always) nonnative species which spread rapidly at the expense of native vegetation.
Related resource topics for county planning include:
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“Outside of their native origins, noxious weeds become oppressors with no known natural competitors to keep their populations in check. These silent invaders quickly begin to out-compete native plants, … forever changing our landscapes. Unlike other ornamental(s), … noxious weeds are nothing short of ecological time bombs.”
Many species of exotic and invasive weeds exist in the Utah. Some species, however, have more potential to be “injurious to public health, crops, livestock, land, or other property”. The Utah Noxious Weed Act of 2008 had defined 28 noxious weed species into three prioritization categories. In December 2015 the official State Noxious Weed list was updated to include 54 species and prioritization categories were modified as follows:
Class 1A: Early Detection Rapid Response (EDRR) Watch ListDeclared noxious weeds and invasive weeds that are not native to the State of Utah, are not known to exist in the state but pose a serious threat, and should be considered a very high priority.
|Common crupina |
|Syrian bean caper
|Ventenata (North Africa grass)
Class 1B: EDRRDeclared noxious and invasive weeds not native to the State of Utah that are known to exist in the state in very limited population, pose a serious threat to the state, and should be considered as a very high priority.
|Blueweed (Viper's bugloss)
|Common St. Johnswort
|Cutleaf viper grass
Class 2: ControlDeclared noxious and invasive weeds not native to the State of Utah that pose a threat to the state and should be considered a high priority for control. Weeds listed in the control list are known to exist in varying populations throughout the state. The concentration of these weeds is at a level where control or eradication may be possible.
|Purple loosestrife |
Class 3: ContainmentDeclared noxious and invasive weeds not native to the State of Utah that are widely spread. Weeds listed in the containment noxious weeds list are known to exist in various populations throughout the state. Weed control efforts may be directed at reducing or eliminating new or expanding weed populations. Known and established weed populations, as determined by the weed control authority, may be managed by any approved weed control methodology, as determined by the weed control authority. These weeds pose a threat to the agricultural industry and agricultural products.
|Russian knapweed |
|Perennial pepperweed (Tall whitetop)|
|Phragmites (Common reed)|
Phragmites australis ssp
|Perennial Sorghum spp.
|Hoary cress |
|Scotch thistle (Cotton thistle)
|Field bindweed (Wild Morning-glory)
*Bermudagrass (Cynodon dactylon) shall not be a noxious weed in Washington County and shall not be subject to provisions of the Utah Noxious Weed Law within the boundaries of that county.
Class 4: ProhibitedDeclared noxious and invasive weeds, not native to the State of Utah, that pose a threat to the state through the retail sale or propagation in the nursery and greenhouse industry. Prohibited noxious weeds are annual, biennial, or perennial plants that the commissioner designates as having the potential or are known to be detrimental to human or animal health, the environment, public roads, crops, or other property.
|Cogongrass (Japanese blood grass)|
|Myrtle spurge |
|Dames Rocket |
County Listed WeedsWeeds in addition to the State Noxious Weeds declared noxious by local government weed control programs
|Davis County||Morgan County||Salt Lake County||Tooele County||Weber County|
*Added to State Noxious Weed List in December 2015.
State land managers, local governments, and property owners are responsible for controlling weed species on the state’s noxious weeds list, and local weed species of concern if necessary. Weed control includes both lands under local management (roads, right-of-ways, parks, etc.) as well as enforcing weed laws on private lands. State law provides county weed managers the right to treat weeds on private lands (assuming proper notice is provided) if the landowner is unwilling or unable to treat the problem themselves, and seek reimbursement or apply liens for the work.
Local Weed Control Programs Include:
- Davis County Public Works (no online content)
- Morgan County Weed Program
- Salt Lake County Weed Control Program
- Tooele County Road Department
- Weber County Weed Department
County-specific Weed Control assessments and from Utah Association of Conservation Districts (UACD) and Natural Resource Conservation (NRCS):
- Davis County Resource Assessment (2012)
- Morgan County Resource Assessment (2013)
- Salt Lake County Resource Assessment (2013)
- Tooele County Resource Assessment (2013)
- Weber County Resource Assessment (2013)
Regional and State Weed Management Plans Include:
- DWR Invasive Weed Control (2009)
- Antelope Island Resource Management Plan (2009)
- Final Great Salt Lake Comprehensive Management Plan and Record of Decision (2013)
- Utah Strategic Plan for Managing Noxious and Invasive Weeds (2004)
Weeds on federal lands are managed by each land management agency. The US Forest Service (USFS) addresses weeds in their 2003 Revised Forest Plan with the goals of preventing and reducing weeds across the Wasatch Cache National Forest. They further clarified weed management in the 2006 Noxious Weed Treatment Program EIS , in which the USFS targets species from state and local noxious weed lists.
The US Bureau of Land Management (BLM) does not address weeds in the 1988 Pony Express Resource Management Plan.  Information on BLM’s nationwide strategy for weed management is available on their Invasive and Noxious Weeds website.
Prevention and early treatment are the most cost effective best management practices (BMPs). Clearly, small areas are much less expensive to treat than those left to spread across the landscape. However, many weeds have expanded to large-scale infestations and can only be treated with substantial effort and cost. Each species of noxious weed has a unique seed dispersal method, making treatment highly variable across species.
Noxious weeds are easily spread through contaminated agricultural machinery, livestock feed, hay, straw, soils, sod, nursery stock, and manure. Preventive measures begin by thoroughly cleaning agriculture machinery and equipment (which has come in contact with weeds) before it is transported to another location. Vehicles transporting seed, feed, and other agricultural materials should take measures to prevent spilling and spreading materials during transport. Transportation of topsoil, fill materials and construction equipment can also spread weeds.
Once established, weeds must be treated to control further spread. Treatment includes:
- Chemical control and containment (hand, vehicle, aerial)
- Mechanical treatments (mowing, discing)
- Biological (insects, grazing livestock such as goats and cattle)
- Physical (water removal, flooding, burning)
The Noxious Weeds data combined with the Ownership data can be used to identify large infestation areas within the county and the ownership of nearby land.
Cooperative Weed Management Areas (CWMAs): These provide weed control across large lands areas, like watersheds, without specific consideration of land ownership to more effectively treat weeds. CWMAs are also used to coordinate treatment efforts and pool resources. Weed control is most effective when all land managers and landowners act quickly to address infestations when they first begin.
CWMAs and their partners within the WFRC area include:
- Bonneville CWMA.Tooele County, Salt Lake County, Utah Department of Transportation (UDOT), US Bureau of Land Management (BLM), and USFS
- Weber River CWMA. Weber County, Davis County, Antelope Island, Utah Department of Wildlife Resources (UDWR), UDOT, and BLM
- Squarrose CWMA. Tooele County, USFS, Utah School and Institutional Trust Lands Administration, and Utah State University, and BLM
Weed control and treatment resources:
- The UDWR compiled an Invasive Weed Control document which provides specific treatment approaches for seven common noxious weeds.
- Utah State University Extension weed control program provides information regarding noxious weeds across Utah
- Utah Weed Control Association is a professional organization consisting of weed control specialists in Utah
- Natural Resources Conservation Service provides detailed noxious weed information
- UDOT Chemical Guide for State Noxious Weeds
Weeds create significant economic impacts that need to be considered in each county’s resource management plan. Economic losses in the United States from weeds was over $20 billion. It is estimated that without the use of herbicides revenue losses to the agricultural sector would increase about 500%. 
Economic considerations for counties include:
- Direct expenditures. The UDWR allocates $200,000 annually to treat weeds. 
- Reduce Range Carrying Capacity for Livestock and Grazing. Dyers woad infestations can spread 14% a year and reduce range carrying capacity by 38%.  The BLM estimated weed costs in the west for control and lost production at $100,000,000 a year. 
- Wildland Fire. Contiguous patches of weeds pose significant fire risks and seeding after wildfire is a necessity to recruit native species rather than weeds.
- Agriculture. Direct control costs, crop and seed contamination, and equipment cleaning costs.
- Wildlife habitat. Phragmites outcompetes native wetland vegetation and chokes out wildlife. 
- Weed control impacts. Fire is a control method often used to treat phragmites, but smoke is a large air quality issue which must be considered in this region.
- Increased wildfire risk and costs. Many noxious weeds, such as cheatgrass, are very flammable and increase the risk of wildfires. After a fire burns an area infested with noxious weeds, the weeds sprout before native plants and are able to dominate native plant species by quickly taking over water and soil resources. 
|Data Name||Data Explanation||Publication Date||Spatial Accuracy||Contact|
|Surface Land Ownership; use Admin field to identify administrative agency||Updated Weekly||1:24,000||State of Utah School and Institutional Trust Lands Administration (SITLA).
|USFS Invasive Species||Current Invasive Plants feature class contains only the most recent or latest invasive Plant Infestation polygons collected by the National Invasive Plant Inventory Protocol. Metadata||Daily||1:24,000||U.S. Forest Service Invasive Species Mapping;
Natural Resource Information System (NRIS)
|Noxious Weeds in Utah||Identified weed locations in Utah||1/18/2013||Variable||AGRC|
|Early Detection Distribution Maps (EDDMaps)||Early detection and distribution mapping system (requires free log in)||Live data||Variable||Center for Invasive Species and Ecosystem Health|
- Utah State Legislature. 2015. Utah Noxious Weed Act – Administrative Rules. Enacted July 2, 2008, Modified December 15, 2015. (Accessed January 25, 2016.)
- U.S. Forest Service. 2003. Revised Forest Plan for the Wasatch -Cache National Forest, February.
- U.S. Department of Agriculture, Forest Service, Intermountain Region. 2006. Wasatch-Cache National Forest Noxious Weed Treatment Program. Final Environmental Impact Statement. Wasatch Cache National Forest.
- U.S. Department of the Interior, US Bureau of Land Management. 1988. Proposed Pony Express Resource Management Plan and Final Environmental Impact Statement. Salt Lake District, September.
- Beck, G. K. Economics of Invasive Weed Control: Chemical, Manual/ Physical/Fire, Biological, and Doing Nothing. Invasive Plant Management Technical Webinar Series.
- Utah State University. 2010. Noxious Weed Field Guide 4th Edition.
- Utah Weed Control Association. 2004. The Utah Strategic Plan for Managing Noxious and Invasive Weeds.
- Utah Department of Natural Resources, Utah Division of Wildlife Resources. 2009. Information Document for Invasive and Noxious Weed Control Project on Utah’s Waterfowl Management Areas. Publication No. 09-14, Salt Lake City, Utah.
- U.S. Department of the Interior, Bureau of Land Management, Oregon State Office. 1985. Northwest Area noxious weed control program: Environmental Impact Statement–Final. Portland, OR: U.S. Department of the Interior, Bureau of Land Management, Oregon State Office.
- U.S. Department of the Interior, Bureau of Land Management. 2011. “Noxious Weeds – A Growing Problem Uintah Basin Weed Management Partnership.” Accessed: 2/15/16.
- Schuske, K. 2013. An Invasive Grass Is Choking Utah’s Wetlands. Explore Utah Science. Accessed: 2/15/16. .
- Idaho Firewise. 2015. Wildfire and Idaho Landscape. Website accessed: 2/16/16.