First reported in the wild
Invasive species - risk of Medium Impact
Introduction pathways - 1
Escape from Confinement
Introduction pathways subclass - 1
NAPRA Ireland risk assessed
Deciduous shrub up to 2m in height, leaves 1-3cm obovate (ovate with the narrower end at the base) and green to purple, flowers yellow and red up to 20mm, fruit bright red (Stace, 1997).
To date there are no impacts recorded for this species in Ireland due to its limited distribution. However in the United States it has become a major pest species in deciduous woodlands, forming dense thickets and smothering native vegetation (Ehrenfeld, 1997). The plant is not browsed by deer in the United States, so control once established is costly as Berberis control needs to be accompanied by deer culls in order to be allow the regrowth of native vegetation (Dávalos et al., 2015).
Woodland, forest and other wooded land; Grasslands and landscapes dominated by forbs, mosses or lichens; Constructed, industrial or other artificial habitats
Seeds germinate in May in the United States with the seedlings rapidly becoming established and has relatively low rates of mortality during the first year (Ehrenfeld, 1999). The plant displays a positive density-dependence of recruitment along with an apparent lack of density-dependence of mortality (recruitment is higher and morality is not affected by the number of plants present) allowing dense thickets to form (Ehrenfeld, 1999). Local dispersal of seeds may also occur through small mammals and birds (Ehrenfeld, 1999).
Pathway and vector description
Widely sold as an ornamental plant and as an alternative to Berberis vulgaris.
Mechanism of impact
Competition, Bio-fouling, Other
Found mainly in woodlands (Reynolds, 2002).
Established - Rare/Localised. Only records to date are from Co Waterford though this may be an artefact of recording effort. Sold widely as an ornamental so likely under recorded
Native to Japan (Preston et al., 2004), considered invasive in North America (Ehrenfeld, 1997).
Date of first record category
Fifty year date category
Records submitted to Data Centre in 2021
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How can you help
Report any sightings to the National Biodiversity Data Centre.
Reynolds, S.C.P. (2002) A catalogue of alien plants in Ireland. National Botanic Gardens. Glasnevin, Dublin. Stace, C. (1997). New Flora of the British Isles 2nd Edition. Cambridge University Press, Cambridge. Ehrenfeld, J. G. (1999). Structure and dynamics of populations of Japanese barberry (Berberis thunbergii DC.) in deciduous forests of New Jersey. Biological Invasions, 1(2-3), 203-213. Ehrenfeld, J. G. (1997). Invasion of deciduous forest preserves in the New York metropolitan region by Japanese barberry (Berberis thunbergii DC.). Journal of the Torrey Botanical Society, 210-215. Dávalos, A., Nuzzo, V., & Blossey, B. (2015). Single and interactive effects of deer and earthworms on non-native plants. Forest Ecology and Management. Preston, C.D., Pearman, D. A. & Dines, T. D. 2002. New atlas of the British and Irish flora. An atlas of the vascular plants of Britain, Ireland, the Isle of Man and the Channel Islands. Oxford University Press.