There are more than 100 species of Japanese cherry trees, all of which are ornamental. The cherry fruit we consume is produced on a different kind of cherry tree. Ornamental cherry trees are beloved for their masses of gorgeous white or pink blooms. In the spring, they present a stunning display of beauty in any landscape. Their beauty, however, comes at the price of fragility. Japanese cherry trees can suffer a number of problems.
Japanese cherry trees in general have very thin bark. This makes them easily damaged by pruning tools, lawn mowers or weed whackers. Insects can also penetrate the bark very easily, burrowing holes deep into the wood and weakening the tree. Cold, hard freezes often split the thin bark and the underlying wood of Japanese cherry trees, causing branches to break and fall off.
Susceptible to Diseases
Most varieties of flowering cherry trees are highly susceptible to diseases. Fungus is a problem in these trees. Galls, cankers, leaf spots, powdery mildew and a general decline of the tree (usually caused by root rot) are all symptoms of fungal diseases. Twig blight, which causes the tree to die back from the tips inward, is also common, especially in trees weakened by another problem or by transplanting (something that Japanese cherry trees do not tolerate well).
Plagued by Insects
Insect problems also plague flowering cherry trees. Chewing insects, such as aphids and tent caterpillars, not only put unsightly holes in the leaves of the trees, but secrete a sticky residue (honeydew) that traps fungus spores, which immediately set up shop and begin to multiply. Boring insects (such as the shothole borer) burrow into the tree, often carrying bacterial diseases on their bodies, which rub off inside the Japanese cherry tree and infect it. Scale (an insect) can cover the branches of the tree with their hard bodies. They also secrete honeydew.
Japanese cherry trees are picky about their environment. They need full sun and moist, but very well-draining soil in order to thrive. They cannot be planted too deeply or they will quickly die. Along those same lines, mulch should never be piled up against the trunk of these flowering beauties. They love fertilizer, but should not be fertilized during their first year of growth because the strong nutrients will burn the tree's delicate roots.