Malus toringo (Siebold) de Vriese

Malus toringo is one of the small-fruited East Asian species with a deciduous calyx and at least some lobed leaves. As usually seen in gardens, it is a disease resistant small tree or shrub reaching about 3 m in height, with a somewhat weeping habit; its flowers are white, from pink buds, and its fruits are yellow. A well-grown specimen of a good form is a lovely thing. This is however a more variable species in the wild. Taller trees to 10 m have sometimes been called var. arborescens Rehd. (Rehder in Sargent 1916) although these probably represent one end of a spectrum. Red fruited forms are also common. It is now widely accepted (e.g. Juniper & Mabberley 2019; Royal Botanic Gardens, Kew 2020) that the older name M. toringo should be used, rather than the more familiar M. sieboldii.

Foliage can look very different depending on the season. All the leaves which are preformed in the bud, emerging in spring, are unlobed: these comprise most of the leaves on spurs and the basal leaves of long shoots. Only leaves which are initiated and expand in the same growing season, that is the occasional leaf on a spur and those leaves further from the base of long shoots, may be lobed (H. McAllister pers. comm. 2020). Hence, lobed leaves are absent at first, but become more prominent as the year progresses.

This is primarily a diploid, sexual species which readily produces hybrid seed when outcrossed in collections, although triploids and tetraploids also occur (Höfer & Meister 2010; Gu et al. 2003; Sax 1959, H. McAllister pers. comm. 2020). Var. sargentii (below) is one of these tetraploids. Fiala’s (1994) claim that ‘true’ M. toringo is a yellow-fruited pentaploid, while M. × zumi (which he most unhelpfully calls M. sieboldii (Rehd.) Fiala) is a red-fruited diploid, is made without citing any reference, seems deeply suspect, and has been generally ignored. The status of M. × zumi (q.v.) is very uncertain; in Japan it has usually been treated as M. toringo var. zumi (Matsum.) H. Hara, with leaves not or scarcely lobed (Iketani & Ohashi 2001).

Small-fruited cultivars raised from seed of M. toringo are often listed here uncritically. Some appear to be unhybridized, but many are clearly hybrids, for example the purple-leaved ‘Aros’ and ‘Scarlett’ (see ‘Cultivars A-B’ and ‘Cultivars S’ respectively).

Malus toringo has long been cultivated as an ornamental in Japan and China, and has been used as a rootstock for grafting apples in north eastern China (Gu et al. 2003; Sargent 1916). It was first described scientifically (as a Sorbus) in 1848 by the German Philipp von Siebold, who practised medicine in Nagasaki during the 1820s. Confusingly, the specific epithet is derived from the Japanese name for M. asiatica, a quite different apple, as Rehder makes clear in Sargent (1916). Its introduction by Siebold to western cultivation, initially in Europe, is conventionally placed at 1856 (Bean 1981), although this date falls towards the end of Siebold’s long banishment from Japan under suspicion of spying for Russia. This first introduction was of the smaller, yellow fruited form most often seen today, from Japanese cultivation (Sargent 1916). A taller form was introduced to the Arnold Arboretum from Japan by Sargent in 1882 (Fiala 1994). Numerous introductions have been made by later collectors, from Ernest Wilson onward. John Grimshaw (pers. comm. 2020) claims a specimen from BBJMT 96 as the finest crab in the Yorkshire Arboretum’s collection.

Large, old specimens are uncommon in Britain. Good examples include trees at RBG Edinburgh, one dating from 1905 (9 m × 136 cm, 2014 – The Tree Register 2020). Quite widely hardy in Western Europe, there are several specimens of Japanese provenance at Gothenburg Botanic Garden, some dating from the 1950s (Gothenburg Botanical Garden 2020); it grows as far north as Trondheim, central Norway, where it forms a low, multistemmed tree (NTNU University Museum 2020). monumentaltrees.com (2020) records a large, umbrella shaped specimen in Eindhoven, Netherlands (10.8 m × 149 cm, 2013).

In the past it was very common in the North American nursery trade, but is now rarely offered (Jacobson 1996). It remains common in collections, though, on both sides of the continent, with several wild origin examples from Korea and Japan at the Arnold Arboretum, MA, the Morton Arboretum, IL, and the David C. Lam Asian Garden, Vancouver, BC for example (Arnold Arboretum 2020, Morton Arboretum 2020; University of British Columbia 2020).