This section is from the book "Commercial Gardening Vol2", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Graceful border plants with divided leaves and feathery trusses of blossom. The trade is chiefly confined to nurserymen, who sell the plants for borders, etc. The best-known kinds are: A. chinensis, 3 ft., pink, with a fine variety called Davidi; A. rivularis, 3-4 ft., creamy white, from Nepal; and A. Thunbergi, 2 ft., rose to pure white, Japan. There are several fine hybrids likely to become good garden plants in time. The Astilbes are all easily grown in ordinary garden soil, but prefer the banks of lakes, streams, etc, like the Spiraeas, with which they are often confused. There is a new group called Arendsi, the result of crossing Davidi with Hoteia japonica and Spiroea astilboides. There are several forms with large loose heads of clear rose-pink and rich-salmon flowers.