Kousa dogwood (‘Cornus kousa’) is a small to medium size flowering tree native to China, Japan and Korea, introduced to North America around 1875.
The flowers of Kousa dogwood appear in June, often profusely, after the glossy dark green leaves have emerged. The true flowers are small, greenish and raspberry-like, surrounded by four creamy white bracts that form what we usually think of as the flowers. On a sunny June day, with a blue sky above, Kousa dogwoods in full flower add a sparkle to our landscapes that can be quite dazzling.
In addition to its flowers, Kousas have several other characteristics that make it a handsome choice for year-round interest. Branches are usually layered, growing in an oval to rounded shape, spreading with age. Bark is decorative, thin, orange/gray/brown with peeling scales. Fruits are pinkish to deep red, round 1” balls, also raspberry-like, appearing in August, upright or hanging on a 2” stalk. Fruits persist until about October, by which time they are usually eaten up by birds. In fall, Kousas have great fall foliage which is a lustrous reddish-purple to scarlet and lasts for three to five weeks.
Kousas do best in full sun, make excellent specimen trees (trees used singly as focal points), in groupings and in shrub borders. They work well in residential landscapes, partly because they don’t get too big, and also because their horizontal branching habit softens harsh corners and vertical lines of homes and buildings.
Kousa dogwood had been bred with its cousin, the native Flowering Dogwood (‘Cornus florida’) to produce a huge variety of cultivars with flowers from bright white to pink to red. Cross breeding has also resulted in dogwoods that can tolerate colder temperatures and are more resistant to a disease called anthracnose, which can be a problem with the native dogwood.
The Kousa dogwoods in the photo are white and pink flowering varieties that burst into bloom just in time for the Memorial Day celebration at Medford’s Honor Roll Park on Winthrop Street.
– Aggie Tuden, Medford Tree Warden