S. CHAMAEDRIFOLIA (syn S. ceanothifolia).—Germander-leaved Spiraea. South-eastern Europe to Japan, 1789. Grows about a yard high, with ovate, pubescent leaves, and white flowers. It varies widely in the shape and size of leaves. S. chamaedrifolia ulmifolia (Elm-leaved Spiraea) a twiggy shrub, 3 feet high, with broad leaves and white flowers, is from Siberia. S. chamaedrifolia crataegifolia (Hawthorn-leaved Spiraea) is of stout, half-erect growth, with rather stiff glaucous leaves that are oval in shape, and bright red or pink flowers in fastigiate panicles. From Siberia 1790, and flowering at mid-summer.
S. DECUMBENS (syn S. nana).—Decumbent Spiraea. Tyrol. This is the smallest-growing of the shrubby Spiraeas, rarely attaining to a greater height than 12 inches. It is a neat growing plant, with small oval leaves, and white pedunculate flowers. For planting on the rockwork or in the front line of the shrubbery, this is an invaluable shrub, and soon forms a neat and pretty specimen. It is perfectly hardy.
S. DISCOLOR ARIAEFOLIA (syn S. ariaefolia).—White Beam-leaved Spiraea. North-west America, 1827. This forms a dense, erect shrub about 6 feet high, with elliptic-oblong leaves, and clothed beneath with a whitish tomentum. The flowers are in large, terminal, slender-stalked panicles, and white or yellowish-white. It is one of the handsomest species in cultivation, the neat and yet not stiff habit, and pretty, plume-like tufts of flowers making it a general favourite with the cultivators of hardy shrubs. Flowers about mid-summer. In rich soils, and where partially shaded from cold winds, it thrives best.
S. DOUGLASII.—Douglas's Spiraea. North-west America. This has long, obovate-lanceolate leaves, that are white with down on the under surface, and bears dense, oblong, terminal panicles of rosy flowers. S. Douglasii Nobleana (Noble's Spiraea) is a variety of great beauty, growing about a yard high, with large leaves often 4 inches long, and looser panicles of purple-red flowers. Flowering in July. The variety was introduced from California in 1859.
S. FISSA.—Split-leaved Spiraea. Mexico, 1839. A stout, erect-growing shrub, about 8 feet high, with rather small leaves, angular, downy branches, and long, loose, terminal panicles of small and greenish-white flowers. The leaves are wedge-shaped at the base, and when young have the lateral incisions split into a pair of unequal and very sharp teeth. Flowering in May and June. In the south and west of England it thrives best.
S. HYPERICIFOLIA (syn S. flagellata).—Asia Minor, 1640. A wiry twiggy shrub, fully 4 feet high, with entire leaves, and small, white flowers produced in umbels at the tips of the last year's shoots. It is a pretty and desirable species.
S. JAPONICA (syns S. callosa and S. Fortunei).—Japanese Spiraea. China and Japan, 1859. This is a robust species about a yard high, with large lanceolate leaves, and small, rosy-red flowers arranged in corymbose heads. Flowering at mid-summer. There are several fine varieties of this species, including S. japonica alba, a compact bush about a foot high with white flowers; S. japonica rubra differs from the type in having dark red flowers; S. japonica splendens, is a free-flowering dwarf plant, with peach-coloured flowers and suitable for forcing; and S. japonica superba, has dark rose-red flowers. S. Bumalda is a closely allied form, if not a mere variety of S. japonica. It is of dwarf habit, with dark reddish-purple flowers.
S. LAEVIGATA (syns S. altaicensis and S. altaica).—Smooth Spiraea. Siberia, 1774. A stout, spreading shrub about a yard high, with large, oblong-lanceolate, smooth, and stalkless leaves. The white flowers are arranged in racemose panicles, and produced in May.
S. LINDLEYANA.—Lindley's Spiraea. Himalayas. A handsome, tall-growing species, growing from 6 feet to 8 feet high, with very large pinnate leaves, and pretty white flowers in large terminal panicles. It is the largest-leaved Spiraea in cultivation, and forms a stately, handsome specimen, and produces its showy flowers in great quantities. Flowering at the end of summer.
S. MEDIA (syns S. confusa and S. oblongifolia).—Northern Asia, etc. The pure white flowers of this species are very freely produced in corymbs along the shoots of the previous season during the months of June and July. The lanceolate-elliptic leaves are serrate, or the smaller ones toothed near the apex only. Within the past few years the species has been brought into prominence for forcing purposes, for which it is admirably suited. It forms an upright, branching bush usually about 3 ft. high, and is best known under the name of S. confusa.