Astilbe
(from a, without, and stilbe, brilliancy; in allusion to the inconspicuous flowers of some of the species). ORD. Saxifrageae. Tall branching herbs, with triternate or biternate leaves, allied to Spiraea, from which they differ in having not more than three carpels, eight or ten stamens, and numerous albuminous seeds. They are all more or less graceful, and some indispensable, either when grown in isolated clumps, or intermingled with other herbaceous plants. They thrive well in almost any rich garden soil, preferring damp positions, and are easily propagated by division, which is best done in early spring. A japonica is grown very extensively for decorative purposes, its elegant spikes of pure white flowers rendering it especially valuable. The majority of the plants cultivated are imported, but they may be grown fairly well in this country in heavily manured soil. They should be potted as early as possible in the autumn, and plunged in ashes or fibre outside, when they will soon commence to root, after which they may be placed in heat, and forced as required, always giving an abundance of water. Indeed, the pots may be stood in pans of water, especially when the plants are well furnished with growth.
A. barbata (bearded). A synonym of A. japonica.
A. decandra (ten-stamened). fl. white, in spicate racemose panicles. May. l. biternate; leaflets cordate, deeply lobed and serated, glandular beneath, and on the petioles. h 2ft. to 3ft. North America, 1812.
A. japonica (Japanese).* fl. small, pure white, in large branching racemose panicles. May. l. triternate or pinnate, serrated. h. 1ft. to 2ft. Japan. This is best grown in pots, as early frosts generally cut it down in the open air. SYNS. Spiraea barbata and japonica, also Hoteia and A. barbata.
A. j. variegata (variegated).* l. prettily variegated with yellow; panicles much more dense than the type; indeed, it is far superior in that respect. A. rivularis (brook).* fl. yellowish-white, or reddish, in large panicled spikes. Late summer. l. biternate; leaflets ovate, doubly serrated, villous beneath and on the petioles. h. 3ft. Nepaul. A grand plant for the margins of lakes or damp woodlands.
A. rubra (red).* fl. rose, very numerous, in dense panicles. Late summer and autumn. l. biternate; leaflets oblique, cordated 1in. to 2in. long, with elongated, serrated points. h. 4ft. to India, 1851. A very pretty, but rare species; excellent for long-lower tropical gardening.
A. Thunbergi (Thunberg's).* fl, small, white, very numerous, in erect, much branched, pyramidal panicles, with reddish and slightly downy stalks. May. l. unequally pinnate or bipinnate; leaflets broad, yellowish green, sharply toothed. h. 1 1/2ft. Japan, 1878. This pretty little sub-shrub is extensively propagated on the Continent for forcing purposes.