The next common variety is the sour top blueberry, Vaccinium myrtilloides . This species tends to be more prevalent in mountains or hilly areas. Stems and leaves are covered with tiny hairs and are more branched than are those of the low sweet. Sour top stems grow six to 24 inches tall. Leaves are light green, hairy on the underside and tend to curl down on the edges, earning its other name, velvet leaf blueberry.
Berries are usually smaller and less sweet than the low sweet.
Cultural Practices Wild blueberries are grown on fields that have been developed from native plants that occur naturally in the under story of the forest. Because of the pruning practices employed, only half of the acres are available to be harvested every year. Pruning Until recently, most commercial blueberry fields have been pruned by fire with straw or oil burners. Repeatedly burning fields for a number of years has resulted in a decline in production associated with the destruction of the organic pad and exposure of the rhizomes. Mechanical mowing will produce equivalent yields without depleting the organic pad.