Blueberries are flowering perennials with dark blue/purple coloured berries. The plant belongs to the section of Cyanococcus and the genus Vaccinium (cranberries, bilberries and grouseberries also belong to the genus Vaccinium). Species that belong to this section of Cyanococcus are commonly sold as ‘blueberries’ and originated in North America.
Blueberries are usually elevated, reclining shrubs. Their size varies from 10 centimeters (3.9 inches) to 4 meters (13 ft) in height. The berries are usually 5–16 millimeters (0.20–0.63 inch) in diameter and have a flared crown. The berries are greenish pale at first, then turn reddish-purple and they are a dark blue/purple colour when ripe. The berries are protected by a layer of powdery epicuticular wax, commonly known as the "bloom". Blueberries usually taste sweet and can vary in acidity. They have a sweet taste when mature, with variable acidity.