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1 March 2010

Mahonia aquifolium (Oregongrape)

Datasheet Types: Crop, Tree, Invasive species, Host plant


This datasheet on Mahonia aquifolium covers Identity, Overview, Distribution, Dispersal, Diagnosis, Biology & Ecology, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.


Preferred Scientific Name
Mahonia aquifolium (F.T. Pursh) T. Nutt., 1818
Preferred Common Name
Other Scientific Names
Berberis aquifolium Pursh., 1814
Berberis aquifolium Pursh. var. aquifolium
Berberis piperiana (Abrams) McMinn
Mahonia piperiana Abrams
Odostemon aquifolium (Pursh) Rydb., 1906
International Common Names
holly-leaved barberry
Oregon grape
Mahonie a feuilles de houx
Local Common Names
Mahonia a feuilles de Houx
Czech Republic
mahónie cesminolistá
tysk potentil
var potentil
laiklehine mahoonia
Mahonia faux Houx
Gewohnliche Mahonie
Stechdornblaettrige Mahonie
kerti mahónia
Maonia comune
tysk mure
Mahonia pospolita
tysk fingerort
vanlig femfingerort
vasstandad femfingerort
EPPO code
MAHAQ (Mahonia aquifolium)


Mahonia aquifolium (Oregongrape); habit, showing foliage and fruits.
Mahonia aquifolium (Oregongrape); habit, showing foliage and fruits.
©Meggar/via wikipedia - CC BY-SA 3.0
Mahonia aquifolium (Oregon grape); Dow Gardens, Midland, Michigan, USA.
Mahonia aquifolium (Oregon grape); Dow Gardens, Midland, Michigan, USA.
©Dow Gardens/ - CC BY-NC 3.0 US

Summary of Invasiveness

M. aquifolium was introduced from North America into Europe, where it is an alien invasive, in 1822 (Ross, 2009). There is evidence of a hybrid origin for M. aquifolium, and so it is likely that invasive populations consist largely of hybrids (Ross et al., 2009). As a highly bred species, it is thought to have an advantage over wild relatives due to selection for more flowers and fruit, giving the species a higher reproductive potential (Allen, 2006). Characteristics thought to be indicators of success for this species include high seed production and few specialist herbivores in its new habitat (Allen et al., 2006). This species escapes regularly from cultivation in private and public gardens to form spontaneous woody vegetation (Auge and Brandl, 1997).

Taxonomic Tree

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Notes on Taxonomy and Nomenclature

Mahonia aquifolium is a member of the family Berberidaceae, which comprises 17 genera, with very diverse morphologies (Kim and Jansen, 1998). The genera Berberis and Mahonia are very closely related and their separation is much disputed; some authors have long thought Mahonia to be a subgenus of Berberis (McCain and Hennen, 1982). The genera Berberis and Mahonia are separated only by the difference in leaf forms; the former having simple leaves and the latter, compound (Marroquin and Laferriere, 1997). The taxonomic revision of the genera by Ahrendt (1961) separates Berberis and Mahonia (Ross, 2009). Mahonia is the second largest genus in Berberidaceae after Berberis with approximately 200 species (Ahrendt, 1961), some of which have been placed in Berberis by some authors, others not (Marroquin and Laferriere, 1997). A study by Heidary et al. (2009) comparing amplified fragment length polymorphism (AFLP) markers and morphological traits found that, despite the close phylogenetic relationship between the two genera, Mahonia forms a distinct group from Berberis with a long genetic distance from the other species in the study (Berberis integerrima, Berberis vulgaris, Berberis gagnepainii, and Berberis thunbergii).

Plant Type



M. aquifolium is hermaphrodite and flowers from January to May. Flowers are bright yellow, insect pollinated, and honey-scented in terminal racemes. They consist of several whorls of perianth segments, 3 per whorl. Stamens 6. Leaves are alternate, compound, leathery and glossy; 15-30 cm long with 5-9 leaflets; reddish bronze new growth; purplish bronze in winter. Berries appear from August to October and may remain on the plant until winter. The seeds ripen from August to September. The plant is a self-fertile evergreen perennial shrub growing to 2 m by 1.5 m. It has an informal, irregular form with upright stems with limited branching. Suckers may form colonies. It has a deep vertical taproot and a network of fine roots in the upper layer.


M. aquifolium has a large distribution and its native range includes the western states of North America (Ross, 2009). It occurs from British Columbia to California and from the Pacific coast to Montana and Idaho (Ross and Auge, 2008). Cultivated forms are now naturalized in various natural and semi-natural environments in Europe; M. aquifolium is one of the most successful alien shrubs in central and eastern Germany where it invades semi-natural habitats (Auge and Brandl, 1997).

Distribution Map

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Distribution Table

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History of Introduction and Spread

M. aquifolium was introduced to Europe for horticultural purposes in 1822 and repeatedly after that time. It was first spotted outside gardens in 1860, after a gap of 38 years (Ross, 2009). This species frequently escapes from natural, silvicultural and urban ecosystems, and has been an aggressive invader in some forests of central Germany and other parts of central Europe (Auge and Brandl, 1997).
Cultivated forms are now naturalized in parts of Europe and were intensively bred with related species, especially Mahonia repens and Mahonia pinnata, both also native to North America (Ross and Auge, 2008) and descendants of cultivated forms are also successful invaders in central Europe (Allen et al., 2006).


Introduced toIntroduced fromYearReasonsIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Central EuropeNorth America1822 YesNo  
Western EuropeNorth America1822 YesNo  

Means of Movement and Dispersal

Vector Transmission (Biotic)

  Regional spread depends partly on seed dispersal by vertebrates; the fleshy fruits are particularly liked by birds.  

Intentional Introduction

Introduced for horticultural purposes and grown in private and public gardens as an ornamental plant for its attractive flowers, evergreen foliage and blue berries (Ross et al., 2009).

Pathway Causes

Similarities to Other Species/Conditions

M. aquifolium is similar to Mahonia repens in that the species known as M. aquifolium is thought to be a hybrid introduced as a highly bred ornamental shrub. M. repens has rougher, less glossy foliage, while M. pinnata has broader leaflet shape.


Found in woods and shrublands, conifer forests, and slopes up to 2,100 m altitude (Ross and Auge, 2008).

Habitat List

CategorySub categoryHabitatPresenceStatus
TerrestrialTerrestrial – ManagedUrban / peri-urban areasPresent, no further detailsNatural
TerrestrialTerrestrial ‑ Natural / Semi-naturalNatural forestsPresent, no further detailsNatural
TerrestrialTerrestrial ‑ Natural / Semi-naturalNatural grasslandsPrincipal habitatNatural
TerrestrialTerrestrial ‑ Natural / Semi-naturalScrub / shrublandsPrincipal habitatNatural

Biology and Ecology


  M. aquifolium is a diploid species (2n=28). High genetic diversity is expected in this taxon because invasive Mahonia populations are thought to originate from gardens and are likely to mainly be hybrids of the closely related North American natives, M. aquifolium, M. repens, and M. pinnata (Ross and Durka, 2006). The influence of plant breeding for ornamental traits might increase the chances of naturalization, thus contributing to invasion success.   Research using microsatellite markers showed that invasive populations are clearly separated from native M. aquifolium, and that M. pinnata genes are not present in invasive populations (Ross and Auge, 2008). A further study found that plants from invasive Mahonia populations grow more vigorously (in terms of stem length, aboveground biomass and number of leaves) than native plant populations, and concluded that this is probably the result of selection and hybridization (Ross and Auge, 2008). Clonal growth, seedling recruitment and increased genetic diversity make M. aquifolium an aggressive invader (Auge and Brandl, 1997).  

Reproductive Biology

  Repeated seedling recruitment takes place, leading to a continuous colonization of available space, and sexual reproduction allows for dispersal to new sites and aids in local invasion. Where there is competition, such as with grass, reproduction is via clonal growth by root sprouts and stem layers (Ross and Auge, 2008). Mahonia populations reproduce sexually by seedlings, facilitating regional and local spread; Auge and Brandl (1997) suggested that seedling recruitment and clonal growth are the main reasons why M. aquifolium is such a successful invader.  

Physiology and Phenology

  Invasive Mahonia populations exhibit high phenotypic and quantitative trait variation (Ross et al., 2009). As well as the clonal growth observed in this species, M. aquifolium is thought to adapt easily to disturbed and possibly contaminated soils and is also quite fertile (Sukopp and Wurzel, 2003).  


  In a study on the effect of climate change on central European cities, Sukopp and Wurzel (2003) found that M. aquifolium has become a significant component of Robinia stands. It thrives in older Robinia stands, and is present in old groups of Sambucus. M. aquifolium can be found growing with Ribes aureum although this species is not as shade tolerant as M. aquifolium.  

Environmental Requirements

Partial shade; moist, well-drained, acidic soil; drought tolerant but dislikes hot, dry sites and harsh winds. Dry soil moisture conditions on moist, well-drained, acid loams.

List of Pests

This content is currently unavailable.

Notes on Natural Enemies

The seed-predating fruit fly Rhagoletis meigenii, native to Europe; a native generalist leafhopper Aphrophora alni; and an introduced rust fungus from North America, Cumminsiella mirabilissima, all attack invasive Mahonia populations (Ross and Auge, 2008).

Natural enemies

Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Aphrophora alniHerbivore     
Cumminsiella mirabilissima (rust: Mahonia spp.)Pathogen     
Rhagoletis meigeniiHerbivore

Impact Summary

Environment (generally)Negative

Impact: Environmental

Impact on Biodiversity

  M. aquifolium populations usually consist of distinct patches formed by one or more genets, but the shrub can sometimes cover the entire understorey. It can out-compete native species due to its successful reproductive strategy, i.e. the colonization of available space due to repeated recruitment of seedlings (Auge and Brandl, 1997).

Risk and Impact Factors


Invasive in its native range
Proved invasive outside its native range
Has a broad native range
Abundant in its native range
Highly adaptable to different environments
Tolerant of shade
Has high reproductive potential
Reproduces asexually
Has high genetic variability

Impact outcomes

Modification of successional patterns
Threat to/ loss of native species


Economic Value

  M. aquifolium is used as herbal medicine in human and veterinary medicine; it is antibacterial, the root bark is diuretic, and the fruit is used as a laxative; it is used as a natural dye, and it provides food and cover for wildlife.  

Environmental Services

M. aquifolium may be useful for erosion control, for a part of the growing period (Hudek and Rey, 2009). M. aquifolium has a high tolerance of chemical pollutants and favourable root morphology, which mean that it could be used in urban landscaping and bioengineering; it also has a high abiotic tolerance (Hudek and Rey, 2009).

Uses List

Environmental > Erosion control or dune stabilization
Medicinal, pharmaceutical > Traditional/folklore
Medicinal, pharmaceutical > Veterinary

Prevention and Control

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Chemical Control

Stumps can be painted with 2,4-D, dicamba, glyphosate or triclopyr herbicide immediately after it has been cut down and then retreated until the plant has been killed according to

Links to Websites

Global register of Introduced and Invasive species (GRIIS) source for updated system data added to species habitat list.


AHRENDT LWA, 1961. Berberís and Mahonia: a taxonomic revision. Journal of the Linnean Society: Botany, 57:1-410.
Allen CR, Garmestani AS, LaBram JA, Peck AE, Prevost LB, 2006. When landscaping goes bad: the incipient invasion of Mahonia bealei in the Southeastern United States. Biological Invasions, 8(2):169-176.
Auge H, Brandl R, 1997. Seedling recruitment in the invasive clonal shrub, Mahonia aquifolium Pursh (Nutt.). Oecologia, 110(2):205-211.
DAISIE, 2008. European Invasive Alien Species Gateway.
GBIF, 2010. Global Biodiversity Information Facility. Global Biodiversity Information Facility. GBIF.
Heidary S, Marashi H, Farsi M, Kakhki AM, 2009. Assessment of genetic structure and variation of native Berberis populations of Khorasan provinces (Iran) using AFLP markers versus morphological markers. Iranian Journal of Biotechnology, 7(2):101-107.
Hudek C, Rey F, 2009. Studying the effects of Mahonia aquifolium populations on small-scale mountain agro-ecosystems in Hungary with the view to minimise land degradation. Land Degradation & Development, 20(3):252-260.
Kim YD, Jansen RK, 1998. Chloroplast DNA restriction site variation and phylogeny of the Berberidaceae. American Journal of Botany, 85(12):1766-1778.
Kowarick I, 2005. Urban ornamentals escaped from cultivation. In: Crop ferality and volunteerism [ed. by Gressel, J.]. Florida, USA: CRC Press, 97-121.
Marroquin J, Laferriere JE, 1997. Transfer of specific and infraspecific taxa from Mahonia to Berberis.
McCain JW, Hennen JF, 1982. Is the taxonomy of Berberis and Mahonia (Berberidaceae) supported by their rust pathogens Cumminsiella santa sp. nov. and other Cumminsiella species (Uredinales)? Systematic Botany, 7(1):48-59.
NOBANIS, 2010. North European and Baltic Network on Invasive Alien Species. North European and Baltic Network on Invasive Alien Species.
Ross C, 2009. Invasion success by plant breeding. Evolutionary changes as a critical factor for the invasion of the ornamental plant Mahonia aquifolium., Germany: Vieweg and Teubner, 103 pp.
Ross C, Durka W, 2006. Isolation and characterization of microsatellite markers in the invasive shrub Mahonia aquifolium (Berberidaceae) and their applicability in related species. Molecular Ecology Notes, 6(3):948-950.
Ross CA, Auge H, 2008. Invasive Mahonia plants outgrow their native relatives. Plant Ecology, 199(1):21-31.
Ross CA, Faust D, Auge H, 2009. Mahonia invasions in different habitats: local adaptation or general-purpose genotypes? Biological Invasions, 11(2):441-452.
Sukopp H, 2004. Human-caused impact on preserved vegetation. Landscape and Urban Planning, 68(4):347-355.
Sukopp H, Wurzel A, 2003. The effects of climate change on the vegetation of central European cities. Urban Habitats, 1(1):66-86.
USDA-ARS, 2010. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory.
USDA-NRCS, 2010. The PLANTS Database. The PLANTS Database. Baton Rouge, USA: National Plant Data Center.
Wittig R, 2004. The origin and development of the urban flora of Central Europe. Urban Ecosystems, 7:323-339.

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Published online: 1 March 2010





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