Sorbaria aitchisonii (Hemsl.) Rehd.

A shrub of open, spreading habit, ultimately 10 ft high; branches red when young, perfectly glabrous, and very pithy. Leaves pinnate, 9 to 15 in. long, composed of eleven to twenty-three leaflets. Leaflets narrowly lance-shaped with long tapering points, 2 to 4 in. long, 1⁄4 to 5⁄8 in. wide, evenly, sharply, and rather deeply toothed; green and quite glabrous on both surfaces, stalkless. Flowers white, 1⁄3 in. across, produced during July and August in pyramidal branching panicles from 1 to 11⁄2 ft long, and 9 to 15 in. through; flower-stalks glabrous; seed-vessels red.

Native of Afghanistan, W. Pakistan and Kashmir; discovered by Dr Aitchison in the Kurram Valley, Afghanistan, in 1879; introduced to Kew from Kashmir by R. Ellis in 1880 (there was a second sending to Kew in 1895 by J. F. Duthie, also probably from Kashmir). It is closely allied to S. tomentosa, differing chiefly in the red young bark, the narrower leaves without down and with mostly simply (not doubly) toothed margins, and its larger flowers. On the whole it is superior to S. tomentosa, its foliage being more elegant and its flowers more effective. It is said to be hardy where S. tomentosa will not succeed.