Taxonomy and Botany of Kwanzan Cherry
Prunus serrulata 'Kwanzan' is a widely planted specimen. These flowering trees are classified as deciduous. These plants are members of the rose family.
Facts About This Tree
Kwanzan cherry grows to about 25 feet in height, with a similar width. Its double, light pink spring blossoms will be most impressive when the tree is grown against a dark backdrop of evergreen trees, be it large ones such as Eastern white pines or smaller fry such as 'Emerald Green' arborvitae (your choice in backdrop will depend on factors such as how large your property is).
Kwanzans are among the most popular cherry blossom trees; in fact, they are one of the stars of the annual show in Washington, D.C. known as the "Cherry Blossom Festival." They produce no fruit, which is a plus for those who desire low-maintenance landscaping (since there will be no mess to deal with). The trees bear coppery leaves in spring and a fall foliage that starts out yellow and morphs into an orange. The fall leaves do not, however, remain long enough on their branches to consider the trees superior fall foliage specimens.
When choosing between the various types of medium-sized ornamental cherry trees, Kwanzan is a good choice if you want an upright, vase-shaped growth habit. If you want a weeping form, select weeping Higan. If your tastes lie somewhere in-between, the popular Yoshino may be right for you.
Planting Zones, Sun and Soil Requirements, Landscape Uses
Grow Kwanzan cherry in full sun and in a well-drained soil with plenty of humus. Keep the soil evenly moist, because this is not a drought-tolerant tree. If you are going to grow a ground cover under your tree, it is advisable that you choose the plants to be grown underneath carefully. The display of a ground cover that blooms just after Kwanzans are done flowering will be spoiled by all of those spent flowers from the tree falling to the ground.
That would be a waste of the ground cover to some degree; it would be better to grow it somewhere else, where you will be able to appreciate its floral display more fully.
Meaning of Name, "Kwanzan" -- Nothing to Do With "Kwanzaa"
While it is tempting to think Prunus serrulata 'Kwanzan' has something to do with the African celebration, Kwanzaa, this does not appear to be the case. According to the U.S. National Park Service, Kwanzan cherry trees were named after a mountain in Japan. Misspellings of the name abound, attributable, at least in part, one would suspect, to this false association with said winter celebration. Thus you will sometimes see "Kwanza cherry" or even "Kwanzaa cherry."
Care for Kwanzan Cherry: Borer Control, Repairing Bark-Splitting
Peach tree borers are a pest problem for these (and other) cherry trees. In fact, their susceptibility to a number of pests earns them the dreaded "short-lived trees" label (they will live only 20 years on average). For borer control, most experts simply advise keeping the tree vigorous (and therefore less susceptible to borer attack) by providing adequate irrigation and fertilizer.
To fertilize organically, back-fill with some compost when planting and top-dress periodically thereafter, watering the nutrients into the soil.
But a couple of experts offer suggestions for more rigorous borer control.
The North Carolina State Extension advises that the "best time to apply a preventative spray to the base of peach trees is August 15 and again September 1." But once the caterpillars get under the bark, they warn, all hope is lost.
The University of California's integrated pest management experts offer tips that go beyond prevention. Spring is the time to implement the following borer control method:
"Treat affected trees with insecticide by spraying the trunk from the scaffold to the soil line. Apply the insecticide with a hand-held sprayer to the tree trunk from the juncture of the main scaffold limbs to the soil line.
Cover the trunk thoroughly, using enough spray material so it will run off to form a small puddle at the base of the tree. Use from 0.5 to 1.5 gallons per tree, depending upon the size of the trunk."
Other small pests that trouble this tree are scale insects, spider mites, and aphids. You can generally blast these pests off the leaves with a strong spray from your garden hose. A bit larger are the tent caterpillars that will eat the leaves; remove their silky nests as soon as you spot them, before much damage can be done. Happily, these are deer-resistant trees, at least.
A more significant problem is bark-splitting, whereby large cracks emerge in the trunk. As Cornell University's Plant Disease Diagnostic Clinic observes, such a crack can "allow entry of disease organisms which can cause decay." As a solution to this problem, the clinic recommends tracing with a knife just outside the split in the trunk, after which you would "remove the bark from inside the traced area." This will prevent the crack from expanding and, if the tree is otherwise healthy, the area should callous over, preventing the incursion of disease organisms.