Grow your own: Consider the other dogwood, Kousa
Monday, October 4, 2010
The soft, pinkish red of Kousa dogwood fruits, some still hanging on trees, does hint at luscious flavor. Some people see their shape as something like a combination of strawberry and raspberry, which adds to the appeal. But doesn't that shape -- a studded sphere -- look more like a medieval weapon than a strawberry or raspberry? Yes, the fruits are edible, but they aren't very palatable. They have a rubbery skin over mealy, just slightly sweet flesh.
I suggest enjoying the fruits only with thine eyes. In fact, enjoy the whole tree with thine eyes, for it is among the prettiest of trees. The Kousa dogwood has something to offer in every season. Now, it is the fruits; soon it will be the color of the leaves as they turn a deep red. Then, winter will highlight the neat form of the plant, upright when young and more spreading with age, in all growth stages branching down to ground level. Age also brings on a pleasant mottling of the bark, a jigsaw pattern of gray, tan and brown.
Spring finds Kousa dogwood at its most dramatically beautiful. It is then that the large, white blossoms -- each up to 4 inches across -- unfold in profusion from branches at the top of the tree right down to those near the ground. Kousa's blossoms resemble those of its cousin, our native flowering dogwood. The four "petals" -- botanically, they are bracts rather than petals -- open creamy white, tapering to a point at their ends and, in the case of Kousa, turning pinkish as they age.
The main difference in flowering between Kousa dogwood and our native flowering dogwood is timing. Kousa dogwood's blossoms unfold two to three weeks after those of flowering dogwood, during that period of calm that follows the springtime burst of bloom from many trees and shrubs. The whole effect is different beyond mere timing, though, because Kousa's leaves have also come out by the time the blossoms appear, so they lend a soft backdrop to the profuse show.
In many ways, Kousa dogwoods, which come from Asia, have it over our native flowering dogwoods. While both trees enjoy similar acidic, moist, well-drained soils, Kousa dogwoods are more tolerant of less-than-perfect conditions. For best flowering, they do need a bit more sun than flowering dogwoods, though. Kousa dogwoods also are resistant to the anthracnose disease that plagues flowering dogwoods. And Kousa dogwoods stay in bloom longer, with their flowering season often stretching on for six weeks.
More than 30 years ago, Elwin Orton at Rutgers University recognized that Kousa dogwoods and flowering dogwoods each had good things going for them, so he initiated a breeding program to combine the best qualities of both. What resulted was the Stellar Series of dogwoods, hybrids with characteristics intermediate between the parents. Some of those varieties include early blooming Ruth Ellen, dwarf Star Dust and pink-flowered Stellar Pink.
Of course, if what you want is later bloom, excellent disease resistance, a tree that branches right down to the ground, and a plant generally better adapted to cultivation, then go ahead and stick with pure Kousa dogwood. Even within this species, there are many varieties from which to choose. For instance, the variety Dwarf Pink sports pink blossoms on a tree growing only 9 feet tall. Branches of Elizabeth Lustgarten weep to the ground, while upright branches give Fanfare a narrow profile. A band of golden yellow is painted down the center of each leaf of Gold Star.
And sure, you might even plant a variety of Kousa notable for its fruits. The variety National has particularly large ones, and those of Xanthocarpa are yellow. Go ahead and taste them if you must, but don't expect much. -- AP