Sour Cherry

Sour cherry trees are typically planted as young seedlings in early spring, set about an inch deeper than they grew in the nursery with broken or overly long roots trimmed away; mulching the trunk with sawdust or wood chips during the first few years helps conserve moisture. Because the tree is self-fruitful, a single tree can set fruit without a second variety nearby, though suckers spreading from the base need removal to keep the planting from thickening into stands.

Choose a site in full sun with deep, fertile, moist but well-drained soil; sour cherry tolerates cooler, more humid conditions and is more cold-hardy than sweet cherry. Trees are spaced more closely than sweet cherry and pruned harder to stimulate new shoot growth, trained to a modified central leader or open-center form, with fertilizer applications adjusted to the amount of annual shoot growth produced.

Sour cherry attracts numerous insect pests, including cherry fruit fly, black cherry fruit fly, cherry fruitworm, mineola moth, green fruitworm, black cherry aphid, cherry leafminer, American plum borer, peachtree borer, and plum rust mite. Birds also strip the ripening fruit, so netting is commonly used to protect a crop.

The tree is susceptible to a long list of fungal, bacterial, and viral diseases, among them black knot, bacterial canker, brown rot, cherry leaf spot, powdery mildew, crown gall, and viruses such as prune dwarf virus (sour cherry yellows) and necrotic ringspot virus. Environmental stresses including drought, waterlogged "wet feet" conditions, and winter injury also damage the crop, and the fruit itself is prone to cracking.

Sour cherries ripen from June into early August, each fruit persisting on the tree for roughly two and a half weeks before it is picked. The cherry industry has been shifting toward mechanical harvesting rather than hand-picking. Once picked, the fruit is used fresh or dried to keep it for later use.

Culinary: Sour cherry is grown chiefly for its acidic fruit, eaten fresh, dried, or baked into pies, and processed into juice, canned fruit, brandy, liqueurs, and preserves.

Medicinal: In traditional medicine, tart cherries have historically been used as a preventive preparation against cardiovascular ailments, inflammatory conditions, and other chronic complaints.

Prunus cerasus is a tetraploid thought to have arisen as a natural hybrid of sweet cherry (Prunus avium) and the European dwarf cherry (Prunus fruticosa) on the Iranian Plateau or in Eastern Europe, where the two parent species overlap; the resulting hybrids stabilized and interbred into a distinct species. Cultivated sour cherries were selected from wild specimens found around the Caspian and Black Seas and were already known to the Greeks by 300 BC. Persians and Romans also grew the fruit, and Roman introduction is said to have brought it to Britain before the 1st century AD; by the 12th century a Morello-type sour cherry was already established in the Schaerbeek region of Belgium.