Blueberries are usually prostrate shrubs that can vary in size from 10 centimeters (4 inches) to 4 meters (13 feet) in height. In commercial production of blueberries, the species with small, pea-size berries growing on low-level bushes are known as “lowbush blueberries” (synonymous with “wild”), while the species with larger berries growing on taller, cultivated bushes are known as “highbush blueberries”. Canada is the leading producer of lowbush blueberries, while the United States produces some 40% of the world supply of highbush blueberries.