Go to many an old farmstead or plantation in the spring and you will find loose, willowy shrubs laden with delicate white flowers. The common name, bridal wreath spiraea (Spiraea thunbergii), evokes images of rosy cheeked brides with flowers in their hair. Despite the beauty of the flowers, the plant's other charms leave something perhaps to be desired and is, at best, a one season plant. That is until the introduction of a gold foliaged form from Japan named 'Ogon' or Mellow Yellow™ as it is often known to American gardeners, the demure, springtime beauty has become a summertime sizzler.
Golden bridal wreath spiraea, like its green-leafed parent, flowers in early spring before the foliage emerges. Masses of pure white flowers cover the shrub lighting up the landscape whether in masses or tucked in among other shrubs. As the flowers begin to fade, the gold foliage starts to expand sending a shock through the garden. The leaves are narrow and retain their color in the sun throughout the season. As summer progresses, the foliage color goes from bright yellow to chartreuse and then gold in the fall. The plant itself will ultimately grow to 3' to 5' tall and slightly narrower with a loose, informal shape. The winter twigs are very fine textured.
Like most spiraeas, 'Ogon' prefers full sun to partial shade and color is best in full sun situations. Unlike many gold foliaged plants, this one will not burn so long as it receives adequate summer moisture. Bridal wreath spiraea will put out maximum growth in a rich, organic soil, but is very tolerant of less than ideal situations as demonstrated by its ability to continue to live at old home-sites long after the home has disappeared. It should be pruned immediately after flowering if desired and will certainly benefit from a trim every couple of years to keep the loose shape in control.
The bright foliage of 'Ogon' spiraea lends itself to bold mass plantings where it will wow people from quite a distance. It is also effective as a single plant mixed in with broad leafed evergreens or in the middle of a perennial border. The fine texture and blowsy habit prevent it from working well as a specimen. Look for the Arboretum's plant at the west end of the Mixed Border.