Photo: Kochia in southwest Montana. © 2020 Delena Norris-Tull
Federal Definitions of Noxious Weeds
Summary and commentary by Dr. Delena Norris-Tull, July 2020.
In a review of the websites for the Federal Agencies that are involved with land management, I found inconsistencies in the definitions for “noxious weeds” and “invasive species.”
The website for the U.S. Natural Resource Conservation Service (NRCS), the Federal agency that provides consultative services and financial assistance to improve the land, for farmers, ranchers, and forest landowners, lists the definition of a “Noxious Weed” as:
The U.S. Bureau of Land Management (BLM) website states that, “Federal and/or State law designates plants as ‘noxious’ if they are overly aggressive, difficult to manage, parasitic, poisonous, carriers or hosts of serious insects or diseases. Noxious plants may also be non-native, new to, or not common to the United States. In most cases, noxious weeds have a direct impact on croplands. The BLM is also concerned with other invasive weeds that cause harm, but may not necessarily be designated as Federal or State noxious listed weeds.”
The BLM website also states: “The term ‘weed’ means different things to different people. In the broadest sense, it is any plant growing where it is not wanted. Weeds can be native or non-native, invasive or non-invasive, and noxious or not noxious. Legally, a noxious weed is any plant designated by Federal, State or county government as injurious to public health, agriculture, recreation, wildlife or property (Sheley, Petroff, & Borman, 1999). A noxious weed is also commonly defined as a plant that grows out of place and is ‘competitive, persistent, and pernicious’ (James, et al, 1991).”
The BLM website further confuses the definition by stating the following: “Are invasive plants the same as noxious weeds? Not necessarily, although many noxious weeds are invasive. Invasive plants include not only noxious weeds, but also other plants that are not native to this country or to the area where they are growing. The BLM considers plants invasive if they have been introduced into an environment where they did not evolve. As a result, they usually have no natural enemies to limit their reproduction and spread (Westbrooks, 1998). Some invasive plants can produce significant changes to vegetation, composition, structure, or ecosystem function (Cronk & Fuller, 1995.)”
It is both striking and concerning that the Federal definitions do not exclude native species from designation as noxious weeds. Indeed, in the Northwestern States, Rocky Mountain Juniper, a native species, has recently been treated as a noxious weed (although it is not included on any official lists of noxious weeds) by a number of States and by both the BLM and the USFS, because it has been found to be encroaching on sagebrush habitat, which then impacts local populations of the potentially endangered Greater Sage Grouse.
While a number of Western States do not allow native plants to be designated as noxious weeds, about half of the Western States do allow native plant species to be designated as noxious weeds. Refer to the section “State Laws” for a detailed list. Also refer to the chapter “Native Plants” for further information on why native species should not be treated as weeds.
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Summary and commentary by Dr. Delena Norris-Tull, July 2020.
In a review of the websites for the Federal Agencies that are involved with land management, I found inconsistencies in the definitions for “noxious weeds” and “invasive species.”
The website for the U.S. Natural Resource Conservation Service (NRCS), the Federal agency that provides consultative services and financial assistance to improve the land, for farmers, ranchers, and forest landowners, lists the definition of a “Noxious Weed” as:
- “Any plant that may render land unfit for agriculture, forestry, livestock, wildlife, or other beneficial uses
- Any plant that may harm native plant communities
- Any plant designated on county or state lists as a noxious weed”
The U.S. Bureau of Land Management (BLM) website states that, “Federal and/or State law designates plants as ‘noxious’ if they are overly aggressive, difficult to manage, parasitic, poisonous, carriers or hosts of serious insects or diseases. Noxious plants may also be non-native, new to, or not common to the United States. In most cases, noxious weeds have a direct impact on croplands. The BLM is also concerned with other invasive weeds that cause harm, but may not necessarily be designated as Federal or State noxious listed weeds.”
The BLM website also states: “The term ‘weed’ means different things to different people. In the broadest sense, it is any plant growing where it is not wanted. Weeds can be native or non-native, invasive or non-invasive, and noxious or not noxious. Legally, a noxious weed is any plant designated by Federal, State or county government as injurious to public health, agriculture, recreation, wildlife or property (Sheley, Petroff, & Borman, 1999). A noxious weed is also commonly defined as a plant that grows out of place and is ‘competitive, persistent, and pernicious’ (James, et al, 1991).”
The BLM website further confuses the definition by stating the following: “Are invasive plants the same as noxious weeds? Not necessarily, although many noxious weeds are invasive. Invasive plants include not only noxious weeds, but also other plants that are not native to this country or to the area where they are growing. The BLM considers plants invasive if they have been introduced into an environment where they did not evolve. As a result, they usually have no natural enemies to limit their reproduction and spread (Westbrooks, 1998). Some invasive plants can produce significant changes to vegetation, composition, structure, or ecosystem function (Cronk & Fuller, 1995.)”
It is both striking and concerning that the Federal definitions do not exclude native species from designation as noxious weeds. Indeed, in the Northwestern States, Rocky Mountain Juniper, a native species, has recently been treated as a noxious weed (although it is not included on any official lists of noxious weeds) by a number of States and by both the BLM and the USFS, because it has been found to be encroaching on sagebrush habitat, which then impacts local populations of the potentially endangered Greater Sage Grouse.
While a number of Western States do not allow native plants to be designated as noxious weeds, about half of the Western States do allow native plant species to be designated as noxious weeds. Refer to the section “State Laws” for a detailed list. Also refer to the chapter “Native Plants” for further information on why native species should not be treated as weeds.
Next Sections: