Spiraea is a genus of flowering plants in the shrubs family of Rosaceae, comprising 80-100 species. It is native to temperate Northern Hemisphere, with the highest species divesity in eastern Asia. It is commonly known as Meadowsweet.
Spiraea species are useful in mixed or shrub borders and smaller forms are suitable for rock gardens. Spiraea species are food plants for larvae of some Lepidoptera species such as Brown-tail, Emperor Moth, Grey Dagger, Hypercompe indecisa and Setaceous Hebrew Character.
Spiraea japonica (Japanese Spiraea), 1.8 x 1.5 m, is a deciduous, perennial shrub native to Japan, China, and Korea, with the center of species biodiversity in China. It has since naturalized throughout much of the northeast, southeast, and midwest areas of the United States, and parts of Canada. Spiraea japonica has alternate, simple leaves on wiry, freely branching, erect stems. The stems are sometimes hairy, brown to reddish-brown, and round in cross-section. The leaves are dark green, alternate, ovate, and with toothed margins. Clusters of white or rosy pink flowers are borne at the tip of the branches in mid- to late summer. This species is found growing along streams, rivers, forest edges, and roadsides.
Many attractive cultivars have been developed from Spiraea japonica, such as 'Anthony Waterer' which has dark leaves and dark pink flowers. 'Goldflame', 75 cm high and across, has yellow-green leaves which are sometimes marked with red, and dark pink flowers.
Spiraea thunbergii (Thunberg's meadowsweet, baby's breath spirea), 1.5 - 1.8 m high and across, is a small, long-lived shrub with thin, flexible stems, native to Japan and China. It is a popular shrub in southeastern United States. It has semi-deciduous, alternate, simple, and almost linear leaves. In early spring and late autumn, white flowers are borne.
Spiraea species is hardy, trouble free and grows well in full sun and well drained soil. Propagation is by greenwood cuttings in summer.