Although there are more than 2,000 different varieties of plums (Prunus domestica), these juicy stone fruits can be broken into three main types: American, European and Japanese. Regardless of the variety, the fruit's shape is typically round, although it can also be heart shaped or oval. Additionally, the color of the skin varies from bluish-black to red, purple, green or yellow.
European varieties such as Seneca and Stanley are among the most frequently planted types of plums in the United States. The fruit is typically uniform in size and well suited to eating cooked, fresh or canned. Japanese plum varieties such as Santa Rosa and Satsuma are juicier than European plums, although they are typically less sweet. American plum varieties such as Blackamber or the hardy beach plum are generally easy to grow in a variety of climates. The fruit is sweetest when it's allowed to ripen on the tree.
When buying plums, customers should look for fruit that yield to slight pressure and are a bit soft at the tip. The skin should be free of any decay, bruises or punctures. Plums are best left to ripen at room temperature with the fruit checked daily to avoid it becoming overly ripe. Fresh plums are typically in season from May through early autumn.