Bitter cherry is also called pie cherry, tart cherry and sour cherry. Bitter cherries are fragile fruits that can be easily damaged after they become ripe. This requires special handling of bitter cherries as soon as they ripen on the tree and once they are harvested. Without the right handling, bitter cherries will bruise, turn brown or become infected with fungi that render the cherries inedible. Cherry harvest time generally falls in the middle of the summer in most areas.
Allow bitter cherries to ripen on the trees. Unlike some fruits, such as bananas, they will not ripen further after being picked. The short shelf life of cherries does not allow them to last long after they have been harvested, so cherries must fully ripen before harvesting.
Wait two to three months after the bitter cherry tree blooms. This two- to three-month period is the most likely time for the cherries to become ready to harvest.
Watch for color changes in the cherries to determine whether they are ripe. They will be dark reddish-brown when ripe. Another method is to pull on a cherry gently to see how difficult it is to pull a cherry loose from its stem. If it is difficult to pull the cherry from the tree, it is likely not ripe yet.
Pick the cherries, or shake the tree to harvest the cherries. Commercial cherry harvest is done by shaking the trees with a machine. Simulate this at home by placing plastic sheeting under the cherry tree and catching the cherries in the sheet when they fall from the tree.
Wash and serve the cherries quickly. Cherries have a shelf life of less than two weeks. Placing them into cold water as soon as the cherries are picked can help them to survive a little better if you won't eat them within the first few days. If they are to be used in a few weeks or months, freeze them right away before they grow mold or become discolored.