The black cherry, or prunus serotina, is a weed that grows from Ontario to Florida in the Eastern part of North America. At maturity, it's a 60-foot-tall weed, but a useful one. If you had to choose one tree to make birds happy, this is it.
The black cherry is scraggly in shape, but fruitful. The flowers, dull white and droopy, give rise to enormous quantities of small black cherries, inedible for us but a great source of bird food. The seeds go through the birds, plop onto the ground with a dollop of bird-supplied fertilizer, and produce a gazillion seedlings. In The Origin of Species, Charles Darwin points out the tree's evolutionary genius: "That a ripe strawberry or cherry is pleasing to the eye as to the palate will be admitted by everyone. But this beauty serves merely as a guide to birds and beasts, in order that the fruit may be devoured and the matured seeds disseminated."
But with minuscule, inedible fruit, they're of little culinary use to man. You don't see hordes of tourists returning in mid-July to eat the fruit from the Tidal Basin's 3,750 trees and spit the pits at each other. Human beings have tinkered with cherry trees for centuries, to divide the flowering from the fruit-bearing. In the phrase of The Hillier Manual of Trees and Shrubs, a British-gardener's Bible, we've made the trees "extremely ornamental."*
A thousand years or so ago in Japan, some observer of trees noticed a double flower on a cherry, a blossom with an extra row of petals. The extravagant, fluffy look appealed to human eyes. It was tough luck for the tree that the extra row of petals wiped out the stamens that are essential to reproduction. The stamen—from the Greek stemon, which means a standing base—is the male part of the flower. It's a slender stalk with a sac of pollen on top. Without the stamen, the tree can't produce fruit and offspring. Castration doesn't usually come to mind at Washington's annual cherry blossom festival. But we have essentially given cherry trees a serious disorder of the reproductive system.
In order to multiply, these cherries must depend on a horticulturalist who takes a slice from the tree, causes the slice to root, and thus makes a clone.
The parent of most Japanese cherries is the wild, wonderfully named Yamazakura. Brought from China by Buddhist missionaries in the sixth century, the tree was grown in groves around Buddhist shrines, the pale pink or white blossoms a symbol of purity. (Perhaps purity also implied celibacy?) Japan's famous cherry-blossom viewing parties began in the 16th century. For Japanese culture, the days of falling blossoms are as significant as the days of full flowering. The falling blossoms symbolize the life of the samurai—noble and brief. Stylized cherry blossoms adorned the planes of World War II kamikaze pilots.
Is it desirable for cherry trees to bear fruit? Imagine the mess to clean up on the Tidal Basin paths—mulberries give you the picture. However, also imagine Traverse City, Mich. Sweet cherries are grown commercially in Michigan, as well as in California, Washington state, and Oregon. And Traverse City is the sour-cherry capital, home of the world's largest cherry pie, a boon to the world.
Still, beauty can be its own excuse for being. The most spectacular tree you can have in a garden is the weeping Higan cherry, prunus subhirtella pendula. This weeping cherry has small black inconspicuous fruits favored by squirrels, but it can only reproduce with ease by cloning. The light pink flowers, almost white, cover the branches before the leaves emerge. The branches lean over to touch the ground, or in many Japanese gardens, the lake or pond.
We don't ask azaleas to make nuts, or peacocks to lay delicious eggs. And yet, the fact that it's called a cherry tree does kind of get your hopes up.