Arboretum: Cornus kousa, Kousa dogwood
May 2011
If you love the delicate blooms and fall color of our native Flowering dogwood, Cornus florida, you should know about the tree’s Asian cousin, the Kousa dogwood, Cornus kousa.
Kousa dogwoods bloom two to three weeks later and are less prone to disease and insect damage. Yet the tree’s spring blossoms, scarlet and purple fall foliage, and red fruit are equally attractive.
In addition to different flowering times, it’s easy to tell the trees apart. The leaves are similar, but the Kousa’s four showy white bracts, or petals surrounding the tiny true flowers, are tapered to a sharp point. The tree’s buds also have a sharp point. Then, in the fall, the red fruits are not a cluster of seed pods as on our native tree, but are marble-sized balls that resemble raspberries dangling from long stems.
Cornus kousa grows upright when young, then spreads out 25 to 30 feet with prominent horizontal branches. This tends to show off the blooms to their best advantage. This tree wants full sun and a well-drained soil, though it will tolerate periodic dry conditions. It’s a healthy tree for the home landscape and extends the beauty of spring blooms and adds colorful foliage in the fall.