Plum colored plums are called "purple plums" and are a deep purple color; other plums are reddish purple. Some other plums can be yellow, red, green or even white. The fruit has a groove running down one side, and a smooth stone (seed). The flesh of the fruit is brownish and is very juicy. The skin can be eaten. It can also be used to make jam and the juice can be used to make wine. It is closely related to the apricot.