Berberis bealei

Berberis bealei Fortune (syn.: Mahonia bealei (Fortune) Carrière, M. japonica Thunberg var. bealei (Fortune) Fedde ) (China) – A rare and probably ephemeral escape from cultivation (or possibly a mere established garden throw-out). A single clone was first recorded on the verge of young woodland in Ieper (Tortelbos) in 2016. Since then similar plants - usually solitary individuals - have been recorded in several other localities, e.g. in Kontich (Vuile Plas), Erpe-Mere, Vorselaar, etc.

This species is less hardy than Berberis aquifolium and therefore less frequently cultivated in western Europe. According to van de Laar (1975) it is the least frost sensitive of the Asian species found in horticulture. B. bealei is easily distinguished from B. aquifolium by its persistent, very distinct bud scales and the thicker, glossy and leathery leaves with more numerous leaflets with sharply spinulose margins.

The taxonomy of Berberis bealei itself is not uncontested. According to some authors (e.g. Taylor & Knees 1989) it probably only merits cultivar status, under B. japonica (Thunb.) R. Brown. Both are indeed much alike and, at least in horticulture, more or less intermediate forms (hybrids?) exist (De Koning & al. 2000). In its area of origin, however, both species are distinguished (Junsheng 2011). B. bealei is separated from B. japonica by its slightly or distinctly glaucous-pruinose lower leaf surfaces and its larger berries. Bayton (2017) distinguished both on other grounds: B. bealei has erect inflorescence branches and nearly orbicular, almost overlapping leaflets whereas B. japonica has loose, spreading racemes and leaflets that are longer than wide and with clear space between them. The plant found in Ieper corresponds best with B. bealei (e.g. broad leaflets with yellowish base, short erect inflorescences) although leaflets are more numerous (up to 13) than usually admitted for this species (see van de Laar 1975). It may well be a hybrid, involving both B. bealei and B. japonica, for instance the widely cultivated B. japonica ‘Hiemalis’ that looks very similar.

This species is locally naturalized in the southeastern parts of the United States (Whittemore 1997). In recent years it is increasingly considered invasive there, especially in woodlots in urban environments (Bowen & al. 2002, Allen & al. 2006). See also: http://www.nps.gov/cue/epmt/products/Mahonia%20bealei%202012%20NCREPMT.pdf.
Berberis japonica was reported as self-sown in the British Isles (Clement & Foster 1994).

Selected references:


Ahrendt L.W.A. (1961) Berberis and Mahonia. A taxonomic revision. J. Linn. Soc., Bot. 57: 1-410.

Allen C.R., Garmestani A.S., LaBram J.A., Peck A.E. & Prevost L.B. (2006) When landscaping goes bad: the incipient invasion of Mahonia bealei in the southeastern United States. Biological Invasions 8(2): 169-176. [available online at: http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1017&context=n...

Bayton R. (2017) The identity of Mahonia japonica. Plantsman N.S. 16(4): 244-248.

Brickell C.D. (1979) The hybrids between Mahonia japonica and M. lomariiflora. Plantsman 1: 12-20.

Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.

De Koning J., Van den Broek J.W., Van de Laar H.J. & Fortgens G. (2000) Nederlandse dendrologie (13e druk). H. Veenman & zonen, Ede: 585 p.

Junsheng Y. (2011) Berberis. In: Wu Z.Y. & al. (eds.), Flora of China, vol. 19. Science Press, Beijing and Missouri Botanical Garden Press, St. Louis: 715-771. [available online at: http://flora.huh.harvard.edu/china/PDF/PDF19/Berberis.pdf]

Roloff A. & Bärtels A. (2006) Flora der Gehölze (2e Auflage). Ulmer, Stuttgart: 844 p.

Taylor N.P. & Knees S.G. (1989) Mahonia. In: Walters S.M. & al. (eds.), The European Garden Flora, vol. 3. Cambridge University Press, Cambridge: 371-373.

Van de Laar H.J. (1975) Mahonia en Mahoberberis. Dendroflora 11-12: 18-35.

Whittemore A.T. (1997) Berberis. In: Morin N.R. (ed.), Flora of North America. Vol. 3. Oxford University Press, New York: 276-286. [available online at: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=103816]

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith