Culture
Easily grown in average, medium moisture, well-drained soils in full sun. Tolerates light shade, a wide range of soils and some drought. Prune as needed immediately after flowering to maintain shape.
Best golden foliage occurs in full sun.
Noteworthy Characteristics
Spiraea thunbergii, called Thunberg spirea, baby’s breath spirea or breath of spring spirea, is a dense, twiggy, upright, deciduous shrub with wiry, outward-arching branching. It typically grows 3-5’ tall and as wide, often becoming somewhat open and leggy over time. It is particularly noted for its early spring bloom (April before the foliage) of tiny white flowers (each to 1/3” diameter) in 3- to 5-flowered umbulate clusters. Narrow, linear-lanceolate, sparsely-toothed, pale green leaves (to 1.5” long and to 1/4” wide) have a willow-like appearance. Foliage turns an undistinguished yellow in fall, but is sometimes tinged with interesting orange and bronze hues.
Genus name comes from the Greek word speira meaning wreath in reference to the showy flower clusters seen on most shrubs in the genus.
Specific epithet honors Carl Peter Thunberg (1743-1828), Swedish plant explorer, who introduced this plant to Europe.
'Ogon' is a golden-leaved variety. Narrow, linear-lanceolate, sparsely-toothed leaves (to 1.5" long) emerge golden yellow in spring, mature to bright green in summer and finally turn interesting shades of orange in fall. Leaves have a willow-like appearance. Golden spring foliage color gives way to chartreuse-green if plants are sited in part shade conditions.
Problems
No serious insect or disease problems. Susceptible to many of the diseases and insects that attack other rose family members, including leaf spot, fire blight, powdery mildew, root rot, aphids, leaf roller and scale.
Uses
Foundations, borders, sunny woodland margins.
Interesting specimen.