Duke is a northern highbush blueberry bush. The berries ripen in the early part of the blueberry harvest season. This bush will yield 8 to 12 pounds of berries per year. The size of the berries are medium to large with a good mild flavor. When the Duke matures it will reach a height of 4 to 6 feet, with an compact upright shape. In the fall the leaves will turn orange and yellow. Zone: 3-7. 1 Qr. Size.tissue cultured plants