Mahonia japonica (Thunb.) DC.
Synonyms: Ilex japonica Thunb.; Berberis japonica (Thunb.) R. Br.
An evergreen shrub with stiff, stout, sparsely branched stems. Leaves 12 to 18 in. long, with thirteen to nineteen leaflets, the lowermost pair inserted near the base of the leaf and much smaller than the others; leaflets leathery and fairly rigid, the lateral ones (except the basal pair) lanceolate-ovate or oblong-ovate, 2 to 4 in. long, acuminate and spine-tipped at the apex, obliquely rounded or rounded-cuneate at the base, slightly falcate, armed on each side with three to six spiny teeth (one or two fewer on the inner than on the outer side), terminal leaflet usually broader and slightly longer than the lateral ones, all lustrous green above, yellowish green beneath. Flowers yellow, fragrant, fairly widely spaced on spreading or pendulous racemes 4 to 8 or even 10 in. long, which are borne in clusters of up to ten at the ends of the previous season’s growths; bracts of the individual flowers ovate or lanceolate-ovate, 3⁄16 to 5⁄16 in. long, about 1⁄8 in. wide; flowers stalks slender, about 1⁄4 in. long. Fruits ovoid, deep bluish purple, about 5⁄16 in. long.
This species is cultivated in Japan but is said not to be found wild there. For its occurrence outside Japan, see below. It has been much confused with the related M. bealei and has also hybridised with it in gardens. It therefore seems best to describe this species here and thereafter discuss the two together.
M. bealei (Fort.) Carr. B. bealei Fort. – This species was discovered by Fortune during his visit to China in 1848-9. The plant he first saw was too big to be lifted, but he eventually procured five smaller ones in the Huychow area of Chekiang which, after a sojourn in the garden of T. C. Beale at Shanghai, were despatched to Standish and Noble’s nursery at Sunningdale. Plants raised from these, probably both by seeds and cuttings, were put into commerce by Standish in 1858 (advertisement in Gardeners’ Chronicle 10 April p. 283, of that year). Fortune named the species, and gave an account of its discovery, in Gard. Chron. (1850), p. 212.
M. bealei differs from M. japonica chiefly in its inflorescences and floral bracts. In M. japonica the inflorescences are lax, the flowers well spaced and subtended by bracts which are almost as long as the flower-stalks. In M. bealei the inflorescences are shorter and stouter, erect or slightly spreading, the flowers are more densely set on the axis and subtended by small scale-like bracts which are about 1⁄12 to 1⁄10 in. long and only half as long or less than the flower-stalks. There is no constant and reliable difference between the two species in their foliage, but in M. bealei the leaflets tend to be relatively broader than in M. japonica and often quadrangular-ovate and truncate at the base; the terminal leaflet is usually larger and broader than the lateral ones, but not invariably so.
The confusion between M. japonica and M. bealei started in the article in which Fortune first described the latter species. Lindley, the editor of the Gardeners’ Chronicle, high-handedly entitled the article ‘An Account of the Discovery of a Fine New Evergreen Shrub named Berberis japonica’, although Fortune, in the text, stated expressly that he had considered and rejected the suggestion that his plants were Berberis japonica (i.e., the mahonia originally described by Thunberg as “Ilex japonica”). Sir William Hooker tentatively sided with Fortune against Lindley, and it was under the names Berberis bealei and B. bealei var. planifolia Hook. that two specimens of Fortune’s plants, received from Standish, were figured in 1855 in the Botanical Magazine (t. 4852 and t. 4846 respectively). For some unexplained reason, Standish distributed some of the offspring of Fortune’s original plants as B. bealei, others as B. japonica, as is clear from his advertisements, and also from the fact that the specimen described by Hooker as B. bealei vat. planifolia (Bot. Mag., t. 4846) was received from Standish’s nursery under the label ‘B. japonica’, whereas the plant of t. 4852 was received as B. bealei and figured as such. However, it was as Berberis japonica that the descendants of Fortune’s plants from China were known until recently. When Japanese nurserymen began to export the true Mahonia (Berberis) japonica they added to the confusion by calling it Berberis bealei! The confusion was cleared up by Takeda in his study of the Old World Species of Mahonia, published in Notes Roy. Bot. Gard. Edin., Vol. 6 (1911-17), pp. 224-227, 240-242, but it persisted in gardens until very recently.
The geographical distribution of M. japonica is not known for certain. It is usually said to be a native of Formosa, but this assertion rests on the reduction of M. tikushiensis Hayata to M. japonica, and it is questionable whether these two species are really the same. There is no specimen in the Kew Herbarium from the mainland of China that agrees perfectly with M. japonica; one specimen from Hupeh has inflorescences as in that species, though the bracts are smaller. On the other hand, there is material agreeing well with M. bealei from Hupeh, Hunan, Szechwan, and Formosa. It is possible that M. japonica and M. bealei are really states of one variable species.
Mahonia japonica and M. bealei are both magnificent hardy evergreens, which will thrive under a quite heavy tree-canopy and indeed can be used, where space permits, in much the same way as M. aquifolium. But they are seen to best advantage as specimens. M. japonica, with its spreading or pendulous racemes, is the finer of the two as a flowering-plant. Both flower in late winter and early spring. In his monograph of Berberis and Mahonia the late Dr Ahrendt remarked that ‘many plants raised from seed are hybrids between these two species’ and such intermediates seem to be fairly common in gardens.
From the Supplement (Vol. V)
† cv. ‘Hiemalis’. – Long-cultivated in Britain, though rarely encountered, this cultivar received a three-star rating in the Boskoop trials of 1972-4. The name refers to its tendency to open its flowers soon after midwinter, but its main merit is its vigour and floriferousness. There is an example at Wakehurst Place, Sussex, which came from Messrs Robert Veitch of Exeter in 1927 and is about 5 ft high and 8 ft wide. The leaves are somewhat shorter, with on the average one pair of leaflets fewer than described by Mr van de Laar, but its great age could explain the difference.