The Regulatory Landscape
One of the WIGL Collaborative’s major initial projects was to research and summarize the existing federal, state and provincial laws and regulations that relate to invasive woody plants. The WIGL Collaborative does not advocate any particular regulatory approach; our goal is simply to explain and compare the approaches that have been used. You can use this page to find detailed information about the laws of your country, state or province. You can also use our map tool for an at-a-glance comparison of how the Woody Invasives of the Great Lakes are regulated in the region.
Both the United States and Canada have laws that restrict the importation and movement of certain plants. The Plant Protection Act directs the U.S. Department of Agriculture (USDA) to establish a noxious weed list of harmful plants and to regulate plants that carry pests. The federal noxious weed list includes plant species that are either not in the United States or have extremely limited populations. The goal of the law is to prevent the listed species from being imported, and if they do enter the country, to prevent their spread. Because the WIGL Collaborative chose to focus on species that are currently impacting the Great Lakes region, there is no crossover between our focal species and the federal noxious weed list. USDA Plant Protection Act regulations restrict the interstate movement of barberry species as potential hosts of the fungal crop disease black stem rust. WIGL species common barberry is a known host of black stem rust. Japanese barberry is also a potential host of this fungus, but all commercially traded varieties are rust resistant.
Similarly, Canadian federal law focuses on plants that host pests and diseases that harm agriculture, horticulture or timber. Canada prohibits the import and movement of barberry species including common barberry and certain cultivars of Japanese barberry as potential hosts of black stem rust. It also prohibits the import and movement of all species in the genus Rhamnus including WIGL species common buckthorn due to their ability to carry oat crown rust.
Neither U.S. nor Canadian federal law restricts states or provinces from enacting laws regulating invasive plants within their boundaries.
Legislation: Plant Protection Act
Citation and link to full text: United States Code, Title 7, Sec. 7712
Responsible agency and link to landing page: USDA, Animal and Plant Health Inspection Service (APHIS)
Related regulations: United States Code of Federal Regulations, Title 7, Part 360 (Noxious Weeds), United States Code of Federal Regulations, Title 7, Part 301.38 (Black Stem Rust)
Advisory body and link to landing page: n/a
Roles of legislation and related regulations: The law gives the Secretary of Agriculture the authority to create a federal noxious weed list and regulate plant pests, and establishes prohibited acts. The noxious weeds regulation creates the noxious weed list, lays out permitting procedures, and describes the process through which USDA can be petitioned to add or remove species from the list. The black stem rust regulation limits the interstate movement of barberry species and lays out procedures for certifying a species or cultivar as rust resistant.
Key definition(s): Noxious weeds are plants that can directly or indirectly harm crops, livestock, irrigation, navigation, public health, natural resources, or the environment.
Black stem rust is a fungal disease of grain crops caused by the fungus Puccinia graminis.
Rust resistant species and cultivars of barberry are species or cultivated varieties belonging to the genera Berberis, Mahoberberis and Mahonia that have been tested by USDA, have proven resistant to black stem rust, and have been listed in the regulation.
Rust susceptible species and cultivars of barberry are any species or cultivated varieties belonging to the genera Berberis, Mahoberberis and Mahonia that are not listed in the regulation as resistant. Common barberry (Berberis vulgaris) is a known susceptible species.
Protected areas for black stem rust are states or counties that have eradicated rust susceptible species and cultivars of barberry, have established nursery certification programs, and have been recognized as such through regulation. All Great Lakes states but New York are protected areas.
Federal Noxious Weeds, woody species only (full list in regulation link above):
Acacia nilotica syn. Vachellia nilotica
|Mesquite (25 species)
|Giant sensitive plant
|Tropical soda apple
- Importation of noxious weeds into the United States
- Interstate movement of noxious weeds
- Sale or trade of noxious weeds
- Interstate movement of any rust susceptible species or cultivar of barberry into or through a protected area.
Exemptions: APHIS may issue permits to enable allow the import or interstate movement of a noxious weed. Generally, APHIS will weigh the intended purpose of importing or moving the species against the risk of spread when considering a permit application. A permit can be revoked mid-course if conditions are not followed.
Cultivar exemptions: None, though cultivar variation is listed as a potential reason that a citizen might petition APHIS to remove a cultivar of a listed noxious weed from the list. Rust resistant barberry cultivars are listed as part of the black stem rust regulations.
Process for species selection/addition: The Secretary of Agriculture may add or remove a species from the Federal Noxious Weed List by revising the regulation via the formalized federal rulemaking process. Any citizen may petition USDA APHIS to add or remove a species from the list. Though the regulation does not specifically list the APHIS criteria for evaluating a petition, it is implied that the likelihood of introduction and spread and the potential economic and/or environmental and/or public health consequences likely to result from introduction or spread are important considerations. Petitioners are encouraged to submit information regarding these factors.
Legislation: The Plant Protection Act
Citation and link to full text: Statutes of Canada, 1990, Chapter 22 (Plant Protection Act)
Responsible agency and link to landing page: Canadian Food Inspection Agency (CFIA)
Related regulations: Canadian Statutory Orders and Regulations, 95-212
Advisory body and link to landing page: n/a
Roles of legislation and related regulations: The law broadly establishes the concept of plant pests, gives the Governor in Council the authority to promulgate regulations related to plant pests, gives the CFIA the authority to inspect places and products for plant pests, and establishes prohibited acts. The regulations further detail prohibited acts and inspection protocols. The regulations also include schedules of Prohibited and Regulated Pests.
Key definition(s): A pest is anything that is injurious or potentially injurious, either directly or indirectly to plant health.
Schedule I things are those whose movement is prohibited within Canada.
Schedule I things, woody plant species only (full list in regulation link above):
All plants belonging to the genera Berberis, Mahoberberis, and Mahonia as hosts of black stem rust of wheat (Puccinia graminis) except specific species and cultivars named in the regulation. Common barberry (Berberis vulgaris) and any unlisted cultivars of Japanese barberry (Berberis thunbergii) are Schedule I things.
All plants of the genus Rhamnus as hosts of crown rust of oats (Puccinia coronata)
- Moving, growing, raising, culturing, or producing anything that is a pest or could be infested with a pest
- Moving of Schedule I items from any location in Canada to any other location in Canada
- Importing Schedule I items to Canada without a permit issued by the Minister of Agriculture and Agri-Food.
Exemptions: The Minister of Agriculture and Agri-Food or a delegated CFIA inspector may issue a written exemption that allows a person to move, grow, raise, culture, or produce a pest or a pest host for research purposes if phytosanitary protocols are followed to prevent pest spread, or to dispose of the item using phytosanitary protocols to prevent pest spread.
Cultivar exemptions: Cultivars of Japanese barberry and other barberry species can be exempted as Schedule I things if the cultivars are proven to be stem rust resistant and a petition is made to the Minister of Agriculture and Agri-Food.
Process for species selection/addition: Species are added to the regulations based on the outcome of pest risk assessments. The Minister of Agriculture and Agri-Foods oversees pest risk assessments using International Standards for Phytosanitary Measures, Part 1; Import Regulations and Guidelines for Pest Risk Analysis by the Food and Agriculture Organization of the United Nations.
State and Provincial Laws
Every Great Lakes state and province has one or more laws or rules that impact whether woody invasive species can be moved, grown, marketed, traded or sold. However, these laws can be very different in scope. For example, Wisconsin’s regulations are fairly expansive and cover 35 woody invasive species while Michigan’s and Pennsylvania’s regulations cover two woody species each.
The WIGL Collaborative’s Regulatory Landscape Committee identified four levels of regulation that are often used in state and provincial laws or regulations. These levels are color coded on our at-a-glance map.
Level 1 (most stringent): species are not allowed to be sold and the state may require management of the plants on private property. Jurisdictions generally only require management on private land for species that have either not yet been found in that jurisdiction or have been found only in very small numbers. Law makers have identified a large public benefit in preventing these species from becoming established.
Level 2: species are not allowed to be sold but private land owners are not required to manage any existing populations. This level of regulation is usually placed on species that are already established in the jurisdiction, but law makers have identified public benefits in preventing additional planting and spread of the species.
Level 3: species are allowed to be sold, but must bear labels that warn about invasiveness and/or give special instructions for planting and care. This level of regulation usually indicates that the species are only invasive under certain circumstances or that the negative economic impact of banning sales of the species may be worse than the invasive impacts.
Level 4: species are not regulated and can be grown and sold in the jurisdiction with no restrictions.
Common barberry is the most stringently regulated woody invasive plant. It is known both for its negative impacts on natural areas and as a host of black stem rust, a fungal crop disease. The United States Department of Agriculture forbids importation of common barberry and interstate movement through most of the Great Lakes region (New York is the only Great Lakes state not in the federal protection area for common barberry). Similarly, Canada prohibits importation of common barberry and any movement within the country. Additionally, five Great Lakes jurisdictions (Indiana, Michigan, Minnesota, Wisconsin and Ontario) require owners of land infested with common barberry to treat it. These jurisdictions and Ohio also ban sales of this species, though sale anywhere is extremely unlikely due to the restrictions on interstate transport and the lack of a market.
The next most regulated species is common buckthorn, which is regulated at the federal level in Canada and by seven other jurisdictions. Like common barberry, common buckthorn is damaging to both native habitats and to agriculture as a host of both oat crown rust and soybean aphids.
Third place goes to multiflora rose, regulated by seven state or provincial jurisdictions.
Photo Credit: Superior National Forest, U.S. National Forest Service