By Gary McCuin and Juan Carlos Cervantes

University of Nevada Cooperative Extension

A weed is defined as any plant growing in a location where it is not desired, or at an abundance that is not acceptable. Therefore, all weeds are obnoxious simply because they are not desirable and/or not acceptable. The next classification of weeds, which are more problematic, are “invasive weeds.” An invasive weed is a plant species that can spread rapidly across a landscape. Most invasive weeds can become established in many different types of plant communities. An invasive weed may or may not be classified as a “noxious weed,” and are usually non-native species.

Most problematic and threatening to our local environment and economies are “noxious weeds.” The term “noxious weed” has a legal definition denoting its significance or importance to society. A noxious weed is defined in the Nevada Revised Statutes chapter 555 as “any species of plant which is, or likely to be, detrimental or destructive and difficult to control or eradicate.” Noxious weeds have been determined by a federal, state or county government to be injurious to public health, agriculture, recreation, wildlife, or any public or private property. All noxious weeds are, or have the capacity to be, extremely invasive.

Invasive noxious weed encroachment is a primary threat to the biological diversity of Nevada’s rangeland resources. Invasive plants cause millions of dollars of damage annually in the West to agriculture, recreation and tourism industries. They can replace desirable native vegetation, thereby degrading habitat for wildlife, reducing forage availability for livestock, reducing water quantity and quality, lowering property values, and potentially increasing the threat of fire, which may lead to further environmental degradation and economic loss and can cost millions of dollars to control and mitigate. Wildfire and subsequent loss of sagebrush habitat is the primary risk factor associated with sage grouse and the potential for federal listing under the Endangered Species Act.

Invasive noxious weed species originated on another continent. They readily spread across North American environments similar to their native habitat. When introduced on this continent, few of the external stresses that kept them in check were transferred with them. These adapted plants outcompete native plant species, develop monocultures where only they grow, and change the habitat of native plants and animals. Cheatgrass (Bromus tectorum) is a prime example of a non-native invasive plant species that has, and continues, to cause tremendous ecological and economic damage across the West. Cheatgrass is not considered a “noxious weed” because it has become so widespread there is no possibility of control or eradication. It can be found throughout the lower 48 states, much of Canada and Alaska.

Because the detrimental effects of noxious weeds affect everyone in the community, and the presence or potential presence of noxious weeds respects no ownership boundaries, it is everyone’s responsibility to be on the lookout for invasive weeds and, at minimum, to try to control them on land that they own or manage. Not only is there a legal requirement to control noxious weeds on your property, but more importantly, there should be a mutual desire to protect our environment and the quality of life we enjoy.

Control of noxious weeds is difficult. They spread rapidly and compete aggressively with other plants for light, nutrients and water. Once noxious weeds inhabit a site, they often reproduce profusely, creating dense stands with extensive roots and soil seedbanks that can persist for many years. This is why it is critical to treat noxious weeds as soon as they are detected in an area. As the infestation increases and spreads, so does the difficulty and expense of control. There are 47 weeds listed in Nevada state law as noxious weeds (

Not all 47 plants are currently found in Eureka or White Pine Counties. Hoary Cress (Cardaria draba), also known as short white top, is common to both Ely and Eureka town sites and counties. The following list delineates the most predominant noxious weeds in Ely and Eureka from most to least prevalent:


•Hoary cress (Cardaria draba), aka white top

•Spotted knapweed (Centaurea biebersteinii)

•Scotch thistle (Onopordum acanthium)

•Russian knapweed (Acroptilon repens)

•Dyer’s woad (Isatis tinctoria)


•Hoary cress (Cardaria draba), aka white top

•Musk thistle (Carduus nutans)Black henbane (Hyoscyamus niger)

•Waterhemlock (Cicuta spp.)

University of Nevada Cooperative Extension has a strong motivation to raise community awareness of noxious weeds and the ecological and economical damage our rangelands and communities suffer due to their invasion and infestation.

Both Eureka and White Pine Counties have active weed districts dedicated to noxious weed control in their respective counties. Both counties have conservation districts that are concerned about the deleterious impacts of noxious weeds.

The Bureau of Land Management and U.S. Forest Service actively attempt to identify and control noxious weeds. Nevada Department of Agriculture’s noxious weed program mission is to effectively coordinate resources and efforts toward proactive prevention, control and management of invasive weed species in Nevada to benefit all land users in the state.

The town sites of Ely and Eureka are not included in the weed districts of their respective counties and cannot treat weeds outside of the district. Therefore, it is necessary for residents to identify and control noxious weeds in town in order to reduce the potential for expansion or re-infestation from town properties.

Due to the physical difficulty in controlling noxious weeds across all legal jurisdictions and boundaries, the cost of control, and the potential for even small infestations to escape and expand exponentially across the landscape, homeowners and concerned citizens are urged reach out for information and assistance in the identification and control of noxious weeds.

Please contact your local Cooperative Extension office for assistance, information and other local resources.