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Home > Plants, Pests & Pest Control > Pest Management > Noxious & Invasive Weed Program > NWAC > Risk Assessments > Common Buckthorn

Common Buckthorn Risk Assessment

Common buckthorn has shiny black berries and green leaves.
Common Buckthorn, photo by Minnesota Department of Agriculture

Common Name: European Buckthorn
Latin Name: Rhamnus cathartica L.

Reviewer: Anthony B. Cortilet
Affiliation/Organization: Minnesota Department of Agriculture

Date: 06/03/2013
FILE #: MDARA00023COMBU_2_24_2014

Final Results of Risk Assessment

Review Entity | Outcome

  • NWAC Listing Subcommittee: List as a Restricted Noxious Weed
    Comments: First review 06/20/2013, Final Review 08/12/2013
  • NWAC Full-group: Voted 13 – 0 to remain as a Restricted Noxious Weed
    Comments: Reviewed 12/18/13   
  • MDA Commissioner: Approved NWAC Recommendation
    Comments: Reviewed 2/24/2014


Box Question Answer Outcome
1 Is the plant species or genotype non-native? Yes, native to northern Europe and Asia. Native to Sweden, Russia, Siberia, China, northern Caucasus mountains, and North Africa. Go to Box 3.
2 Does the plant species pose significant human or livestock concerns or has the potential to significantly harm agricultural production?    
3 Is the plant species, or a related species, documented as being a problem elsewhere? Yes, European buckthorn is known to be problematic throughout the northern half of the US and throughout Canada.  Go to Box 6.
6 Does the plant species have the capacity to establish and survive in Minnesota? Yes, buckthorn is well established in Minnesota.  
6A Is the plant, or a close relative, currently established in Minnesota? Yes, European buckthorn has been recorded in all but 2 counties in MN. Go to Box 7.
7 Does the plant species have the potential to reproduce and spread in Minnesota? Yes, European buckthorn has been reproducing and spreading in MN for many decades since its introduction.  
7A Does the plant reproduce by asexual/vegetative means? No. Go to Box 7C.
7C Does the plant produce large amounts of viable, cold-hardy seeds? Yes, European buckthorn produces many fruit-encased seeds that are highly attractive to birds. Seeds can also remain dormant in the seedbank for many years. Go to Box 7F.
7F Are sexual propagules – viable seeds – effectively dispersed to new areas? Yes, Birds are known to be a huge distribution vector for European buckthorn spread. Water, snow, small mammals and human activity are also highly responsible for spread. Go to Box 7I.
7I Do natural controls exist, species native to Minnesota, that are documented to effectively prevent the spread of the plant in question? No, no natural controls are known to exist. Go to Box 8.
8 Does the plant species pose significant human or livestock concerns or have the potential to significantly harm agricultural production, native ecosystems, or managed landscapes? Yes – European buckthorn is a serious threat to native ecosystems and managed landscapes. It has also been linked to agriculture as an overwintering host to the soybean aphid and as an alternate host for alfalfa mosaic virus and crown rust (Puccinia coronata Corda var. avenae), which causes oat rust disease.  
8A Does the plant have toxic qualities, or other detrimental qualities, that pose a significant risk to livestock, wildlife, or people? No, other than habitat degradation. (NOTE: as of time of completing this risk assessment, a publication is forthcoming which produces evidence of laboratory studies that have shown impacts of the chemical emodin (a chemical in the leaves and berries of buckthorn that may have indirect impacts on certain amphibians). Go to Box 8B.
8B Does, or could, the plant cause significant financial losses associated with decreased yields, reduced crop quality, or increased production costs? Not determined at this time in agronomic systems (soybean aphid connection not well defined at this time and no clear impacts on MN Agriculture related to alfalfa mosaic virus and crown fungus). Could be detrimental to forestry operations, but financial losses are not well documented at this time. Go to Box 8C.
8C Can the plant aggressively displace native species through competition (including allelopathic effects)? Yes, European buckthorn infestations have been shown to displace native forest understory and greatly reduce forest biodiversity. European buckthorn infestations have been shown to significantly alter native forest soils, altering natural succession, and creating a more suitable environment for increased buckthorn production and spread. Buckthorn leaves are full of a toxin called emodin that discourages herbivory. Research is being conducted on impacts emodin has on the environment after falling from the tree. Studies have shown emodin can inhibit certain amphibians such as frogs from successful production of offspring. Studies vary on allelopathy for European buckthorn. Some suggest allelopathy is occurring in the soil but cannot determine any single target yet. Other studies suggest that multiple soil changing characteristics in buckthorn populations are simply to blame and not a result of any allelopathy. Go to Box 9.
9 Does the plant species have clearly defined benefits that outweigh associated negative impacts? None that would outweigh the negatives. European buckthorn was once thought to be beneficial as wildlife cover and food in transition areas between forest and grasslands and the berries are sought after by small mammals and birds.  
9A Is the plant currently being used or produced and/or sold in Minnesota or native to Minnesota? No, was sold in Minnesota until becoming a Restricted Noxious Species in 1999. Go to Box 10.
10 Should the plant species be enforced as a noxious weed to prevent introduction &/or dispersal; designate as prohibited or restricted? Yes.  
10A Is the plant currently established in Minnesota? Yes – see Box 6. Go to Box 10B.
10B Does the plant pose a serious human health threat? No – European buckthorn does not pose a serious threat to humans. Go to Box 10C.
10C Can the plant be reliably eradicated (entire plant) or controlled (top growth only to prevent pollen dispersal and seed production as appropriate) on a statewide basis using existing practices and available resources? No – European Buckthorn is hard to control for multiple reasons. It is a forest species which makes traditional large-scale herbicide application unfeasible on large stands. Seed banks continue to produce buckthorn seedlings following treatments requiring long-term management that requires a large commitment of time and financial resources by landowners. Recruitment of seeds from neighboring sources through birds and mammals is problematic in areas being reclaimed or restored. List as a Restricted Noxious Weed.



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