Attractive, hardy perennial, Spiraea-like plants grown for their showy white, pink, rose, purplish and crimson flower plumes, which are in full beauty in June, July, and August. They are natives of China, Japan and Korea and belong to the Saxifrage family, Saxifragaceae. The name Astilbe is derived from a, without, and stilbe, brilliancy, and refers to the insignificant flowers borne by some kinds, though not by those which are cultivated in gardens. In gardens they are often grown under the common name Spirea. Spiraea is the botanical name of an entirely different group of plants. See Spiraea.
Must Be Kept Moist. All are easily grown in deep, moist, loamy soil in a sunny or partly shaded position. They are moisture-loving plants and, if in a sunny place, must be watered abundantly in dry weather; they form a compact mass of roots which dry out quickly. They are useful for planting by the side of a garden pool or pond, or in other damp positions; there, in the course of a few years, they will develop into magnificent specimens which are a glorious sight when in bloom.
Planting and Propagating. The plants may be set in fall or in spring. It is wise to leave them undisturbed as long as possible to ensure large, free-blooming plants. The stock is increased by lifting the plants in spring, separating them into rooted pieces and replanting. Seeds may be sown in light soil in a greenhouse—temperature 50 degrees in March—the seedlings, when large enough, being planted out of doors on a nursery border.
Most Showy Kinds. Numerous hybrid Astilbes have been raised in recent years, some of the loveliest being Betsy Cuperus, flesh-pink; Europa, dark red; Erica, salmon-pink; Fanal, garnet-red; Gertrude Brix, crimson; Granat, crimson; Gruno, salmon-pink; Red Sentinel, red; Prof. Van der Wielan, white; Peach Blossom, soft pink; Deutschland, white; and W. Reeves, deep red. These are favorites for growing in pots under glass as well as for planting out of doors. They are potted in autumn in loamy soil, the pots plunged in ashes out of doors, and transferred to a warm greenhouse or to a sunny window as required for forcing into bloom, plenty of water being given.
Astilbe japonica, sometimes erroneously called Spiraea japonica, 2 ft., has loose panicles of white flowers in June. Other popular kinds are A. Davidii, 4 ft., bright magenta, July;' A. grandis, 4 ft., white, July—August; and A. rivularis, 3-4 ft., ivory or pinkish, July.
For the Rock Garden. Very dainty dwarf kinds suitable for cool, moist situations in the rock garden are A. chinensis pumila, 9 in., mulberry-red; A. crispa, a dwarf hybrid represented by several named varieties, in white, pink and red; and A. simplicifolia, 6 in., white and pink, September.