Spiraea trilobata L.

A twiggy shrub, 3 to 4 ft high, of broad but compact habit, young shoots and leaves glabrous; stems round, often zigzagged in growth. Leaves roundish, 1⁄2 to 1 in. (rarely 11⁄2 in.) long, and about as much wide, coarsely toothed, sometimes obscurely three- or five-lobed, the base rounded or sometimes slightly heart-shaped, rather glaucous green. Flowers white, small, produced during June, packed very numerously in umbels 3⁄4 to 11⁄2 in. across; each umbel terminating a short leafy twig, springing from the previous year’s growth, every flower having a slender, glabrous stalk 1⁄3 to 3⁄4 in. long.

Native of N. Asia, from Korea and N. China to Siberia and Turkestan; introduced in 1801. Although its flower-buds are sometimes injured by frosts, this is a very pretty shrub of neat habit.

S. blumei G. Don S. chamaedryfolia sens. Bl., not L. – A native of Korea and Japan, this is nearly allied to S. trilobata, but differs in the shape of the leaf, which is ovate or lozenge-shaped, longer than it is wide, the base wedge-shaped. Flowers white, crowded in umbels 1 in. wide. A shrub 3 to 6 ft high.

From the Supplement (Vol. V)

S. blumei – This species also occurs in China, and is in cultivation from seeds collected by Stephen Haw in Shantung province in 1981. It was also seen by Roy Lancaster in the Wudang Shan, north-west Hupeh, in 1983.