Sloe is the small, dark purple fruit of the blackthorn bush, scientifically known as Prunus spinosa. These berries are typically about the size of a pea and have a tart flavor, making them less suitable for eating raw. Instead, they are often used to make jams, jellies, and the popular liqueur called sloe gin. The blackthorn bush is a thorny shrub that grows in hedgerows and woodlands across Europe and parts of Asia. Sloes ripen in late autumn, usually after the first frost, which helps to soften their taste. The fruit is an important food source for various wildlife, including birds.