Spiraea japonica L. f.
Synonyms: S. callosa Thunb.
A shrub to about 5 ft high, its branches usually terete, sometimes flattened and angled, glabrous or downy. Leaves short-stalked, lanceolate to ovate (sometimes broadly so), up to 3 in. or so long, acute at the apex, cuneate at the base, sharply toothed or incised, glabrous on both surfaces or downy beneath, the underside green or somewhat glaucous. Flowers about 3⁄8 in. across, rosy pink, produced in July and August at the ends of the current season’s shoots in an often large and complex arrangement of flat corymbs. The whole inflorescence, in some garden clones, may be anything up to 12 in. wide, and consists of a terminal corymb of varying size, around which are arranged supplementary corymbs at the ends of laterals from the upper leaf-axils, which open later; but even on one and the same plant there is great variation in the size and complexity of the inflorescence, depending on the vigour of the shoots; separate and small corymbs are sometimes borne on short laterals lower down the shoot. Inflorescence axes glabrous or downy. Calyx-lobes erect at flowering-time, later spreading. Stamens longer than the petals and a conspicuous feature of the flower. Follicles glabrous except along the suture, erect or slightly spreading.
Native of Japan, with varieties in China, where it is widespread, except in the north. It is represented in the gardens of the western world by cultivars, of which the first to be introduced was the Chinese ‘Fortunei’ (c. 1850), followed by ‘Albiflora’ (to France before 1864) and ‘Bullata’ (before 1881). The others were probably either imported from Japan at a later date or raised in European gardens.
The garden varieties of S. japonica are among the most valuable and trouble-free of late-summer shrubs. They should be pruned in spring by cutting clean out sufficient of the older wood to prevent crowding, and then shortening back those selected to remain.
cv. ‘Albiflora’ (‘Alba’). – An erect shrub of dwarfer and weaker growth than the other garden clones; young shoots downy, distinctly flattened and angled. Leaves light green, lanceolate, slenderly pointed, usually under 2 in. long, glabrous. Flowers white (S. callosa var. albiflora Miq.; S. fortunei alba Hort.; S. callosa alba Clemenceau; S. japonica var. alba Nichols.; S. albiflora (Miq.) Zab.; S. leucantha Lange; S. japonica var. albiflora (Miq.) Koidz.). A pretty shrub, growing to not much more than 2 ft high; introduced to Europe before 1864, probably from Japan.
It is unfortunate that most authorities (outside Japan) have followed Zabel in giving this clone the rank of a distinct species and treating other smaller growing clones with slightly flattened branches as hybrids between this “species” and S. japonica under the name S. × bumalda Burven. sens. Rehd. (S. × pumila Zab.). However, Japanese botanists, followed here, include it in S. japonica, and Dr Hara has pointed out that S. japonica is a variable species and that in Kyushu the branches are usually flattened (Flora of Eastern Himalaya (1966), p. 637).
‘Albiflora’ has given rise to a mutation in which some trusses bear pink flowers.
var. alpina Maxim. – See under ‘Nana’.
cv. ‘Alpina’. – See ‘Nana’.
cv. ‘Atrosanguinea’. – Described by Zabel as having strongly villous inflorescences, dark rose-coloured flowers and persistently hairy stems.
cv. ‘Bullata’. – A dwarf shrub of very compact, rounded habit, rarely more than 12 or 15 in. high; young shoots erect, covered with rusty coloured down. Leaves 1⁄2 to 1 in. long, almost or quite as much wide, broadly ovate, often recurved, coarsely and irregularly toothed, and nearly or quite glabrous on both surfaces except for a few hairs at the base and on the stalk; nerves prominent beneath. Flowers scarlet-rose, small, produced towards the end of July in great numbers in flat branching corymbs 3 in. wide at the end of the current season’s growths; flower-stalks downy (S. bullata Maxim.; S. japonica var. bullata (Maxim.) Mak.; S. crispifolia Hort.).
A Japanese garden variety in cultivation in Britain by 1881. It is one of the dwarfest of spiraeas and one of the prettiest; very suitable for the rock garden or wherever small shrubs can be accommodated, and protected from stronger growing neighbours. The plant is almost hidden by its flowers in July.
Although often treated as a distinct species, it is now generally accepted that it is no more than an aberrant garden variety of S. japonica. The varietal epithet refers to the puckering of the leaf-blade, often noticeable between the veins.
cv. ‘Bumalda’. – Branches downy when young, slightly ridged. Leaves broad-lanceolate, at first brownish red, sharply and deeply toothed, glabrous. Inflorescence downy. Flowers carmine-pink (S. bumalda Burvenich, Rev. Hort., 1891, p. 12; S. × pumila f. bumalda (Burv.) Zab.; S. japonica var. bumalda (Burv.) Bean).
‘Bumalda’, described in 1891, is of unknown origin; Kew received it in 1885 from Froebel of Zürich, but whether he raised it or imported it from Japan has not been ascertained. In foliage and habit it bears a certain likeness to ‘Albiflora’ (q.v.) but the notion that it is a hybrid between it and typical S. japonica is unproven.
As originally introduced, ‘Bumalda’ was a rather dwarf plant with a high proportion of its leaves edged or marked with yellow, or even wholly yellow, but it appears to be an unstable clone.
A few years before 1890 a branch-sport appeared on ‘Bumalda’ in the Knap Hill Nursery, with flowers of a much more beautiful shade of carmine. This is S. japonica ‘Anthony Waterer’ which is now the most frequently planted of the garden varieties. It received a First Class Certificate in 1891. It is itself somewhat sportive and there may be several sub-clones in commerce. A particularly fine form, growing to 4 or 5 ft high, shows no trace of the variegated leaves which the original ‘Anthony Waterer’ inherited from ‘Bumalda’, which, too, may have sported into taller and laxer forms.
cv. “Fastigiata”. – See S. amoena, treated under S. bella.
cv. ‘Fortunei’. – One of the tallest of the garden varieties, growing to about 5 ft high; branches terete. Leaves reddish when young, oblong-lanceolate, 3 to 4 in. long, acuminate at the apex, sharply toothed, glaucous beneath, glabrous on both sides. Flowers deep pink, in large compound, downy corymbs. Bot. Mag., t. 5164 (S. callosa sens. Lindl., not Thunb., sens. strict.; S. fortunei Planch.). This, the first representative of S. japonica in western gardens, was sent by Fortune to Standish and Noble in 1849 or the following year during his second visit to China; they were already offering plants at 10/6 each by the time he returned home in the autumn of 1851. It was the commonest form of the species in gardens for the rest of the century and was considered to represent the typical S. callosa of Thunberg, i.e., S. japonica. Indeed the description of S. japonica in previous editions appears to have been largely based on the Chinese ‘Fortunei’. By the 1930s it had become so rare that a specimen was sent to Kew from an English nursery as a possible new species.
The Fortune introduction is the type of var. fortunei (Planch.) Rehd., a native of E. and C. China, agreeing essentially with the original introduction.
cv. ‘Froebelii’. – Leaves brownish red when young, oblong-ovate, to about 31⁄2 in. long, glaucous beneath, glabrous. Flowers bright crimson, in broad, compound corymbs; pedicels hairy but main inflorescence-axes almost glabrous. Distributed by Froebel of Zürich, before 1894 (S. × pumila f. froebelii Zab.; S. × bumalda f. froebelii (Zab.) Rehd.). A shrub of neat, erect habit, flowering in late summer. The similar ‘Coccinea’ was introduced from Japan by Messrs Gauntlett of Chiddingfold, at an uncertain date.
cv. ‘Glabrata’ (‘Glabra’). – A strong-growing form with corymbs, including the supplementaries, over 1 ft in diameter; flowers rosy pink. Leaves broadly ovate, the largest 4 to 5 in. long and 21⁄2 to 3 in. wide, rounded at the base, and, like the young wood and flower-stalks, glabrous (S. glabrata Lange; S. japonica var. glabrata (Lange) Nichols.).
Of unknown origin, described by the Danish botanist Lange as S. glabrata and introduced to Kew from Denmark; the S. pumila var. glabra of Zabel, sent out by Messrs Hesse, is probably the same clone.
The botanical name var. glabra (Reg.) Koidz (S. callosa var. glabra Reg.) is of general application to glabrous forms of the species. The type was a cultivated plant, but bore no resemblance to ‘Glabrata’, judging from the authentic specimen in the Kew Herbarium.
cv. ‘Goldflame’. – Very effective in spring, the unfolding leaves being rich bronze-red, becoming light russet-orange, but rather jaundiced in appearance by the time the flowers appear; these are deep rosy red, but in rather small widely spaced corymbs. A few leaves are partly deep green and reversion shoots with leaves wholly of that colour sometimes grow out from the base of the plant and should be removed at once. Of American origin, introduced in the early 1970s.
cv. ‘Leucantha’. – A seedling of ‘Albiflora’, with rather larger and relatively broader more coarsely toothed leaves and a larger inflorescence. Flowers white, as in the parent. Raised by Zabel and later distributed by Messrs Hesse (S. × pumila var. leucantha Zab.).
cv. ‘Little Princess’. – See under ‘Nana’.
cv. ‘Macrophylla’. – Leaves as large as in ‘Glabrata’ or larger, but curiously inflated (bullate); inflorescence poor and small. It is really only worth growing as a curiosity, though a redeeming feature is that the leaves colour quite well in the autumn. Put into commerce by Messrs Simon-Louis, with whom it arose as a seedling.
cv. ‘Nana’ (‘Alpina’). – A very dense shrub, attaining after fifteen years or so a height of about 21⁄2 ft and a spread of 6 ft; young stems and inflorescenceaxes finely woolly. Leaves glabrous except at the margin, ovate or elliptic-ovate, mostly 1⁄2 in. or slightly more long, but 1⁄4 in. long on the weakest shoots and around 1 in. long on the strong growths that emerge here and there, rounded to broad-cuneate at the base, with about five pairs of veins. Flowers lilac-pink, starting to open rather earlier than in most garden varieties of S. japonica, mostly arranged in simple corymbs (but compound on the strongest shoots).
Although not outstanding in flower-colour, this makes a neat formal specimen. It needs no pruning beyond a light shearing in spring.
The origin of this variety is unknown. It has also been grown as S. j. alpina and erroneously as S. densiflora. ‘Nyewoods’ is probably the same clone, but ‘Little Princess’, selected in Holland from plants grown as S. j. alpina, is somewhat more robust, with larger leaves.
S. japonica var. alpina Maxim, was described in 1879 from a plant found wild on Mt Hakone in the central island of Japan, with procumbent or erect stems, growing a ‘handbreadth’ high. This variety, according to Maximowicz, was also cultivated in Tokyo gardens. But ‘Nana’ is perhaps of garden origin, since it does not come true from seed as a natural mountain variety might be expected to do, its self-sown seedlings being laxer and with larger leaves, though the characteristic rather woolly indumentum is retained.
cv. ‘Ruberrima’. – Described by Zabel as having flowers coloured dark rose in downy corymbs and soon glabrous stems.
The spiraea once grown at Kew as S. japonica var. ruberrima was a hybrid of S. japonica with either S. bella or S. amoena; it came from St Petersburg. ‘Bumalda Ruberrima’ was raised by Messrs Lemoine by crossing ‘Bumalda’ and ‘Bullata’ (S. × lemoinei Zab.).
From the Supplement (Vol. V)
† var. acuminata Franch. – This is near to var. fortunei and has priority over it at the varietal level. The leaves are usually green beneath, and downy there, at least on the veins (more or less glaucous and glabrous in var. fortunei). Flowers pink, in corymbs up to 5 in. wide. Native of central and western China; introduced by Wilson to the Arnold Arboretum, Massachusetts, in 1908. It is now in cultivation in Britain from seeds collected by the Sino-British Expedition to the Tali range (Cangshan) of Yunnan.
† cv. ‘Crispa’. – Leaves fringed with deep, very narrow teeth. Put into commerce by the German nurseryman Hesse.
† cv. ‘Dart’s Red’. – A sport from ‘Anthony Waterer’, with deep carminered flowers, paling somewhat as they fade. Raised by the Darthuizer Nurseries, Holland (Dendroflora, No. 13/14, p. 54 (1977)).
† cv. ‘Golden Princess’. – Leaves bright gold throughout the summer. Compact and low-growing. A seedling of ‘Gold Flame’, raised by Peter Catt at his Liss Forest nursery and put into commerce by Bressingham Gardens, Norfolk, in 1985. Some pruning in early spring is advisable.
† cv. ‘Shirobana’. – Flowers pink or white, both colours appearing in the same truss but white predominating. Late summer. Habit upright, to about 5 ft. Introduced to Holland from Japan by Messrs Spaargaren and now in commerce in Britain.
† cv. ‘Walluf’. – As described by Krüssmann, this differs from ‘Bumalda’ in showing no variegation and from ‘Anthony Waterer’ in its brighter pink flowers; raised in Germany around 1930. It has been suggested that this is an inconstant sub-clone of ‘Anthony Waterer’, but Graham Thomas tells us that a plant imported by Messrs Hilling before the second world war did not revert.