Highbush blueberries are the most commonly planted type of blueberries. The name actually represents the Northern Highbush (Vaccinium corymbosum) and the Southern Highbush blueberries. Southern Highbush are a hybrid of Northern Highbush and the native Southern species, making it more suitable for the warmer climates of the Southern United States. Lowbush Blueberries (Vaccinium angustifolium) often are referred to as wild blueberries because they grow naturally in Maine, Quebec and Atlantic Canada. Large stands of naturally growing Lowbush varieties are harvested commercially each year, but they are not planted commercially.
Range and Chilling Requirements
All blueberry varieties require "chilling, " that is time spent dormant at temperatures between 45 and 32 degrees Fahrenheit. Lowbush Blueberries, suitable for U.S. Department of Agriculture (USDA) plant hardiness zones 3 to 7, are high chill varieties requiring 1,000 to 1,200 chill hours each winter. Northern Highbush varieties, also suitable for USDA hardiness zones 3 to 7, need slightly less, between 800 and 1,000 chill hours annually. Southern Highbush varieties, suitable for USDA hardiness zones 5 to 10, need the least chilling, between 150 and 800 chill hours.
Highbush blueberry varieties grow in defined bush shapes. Some are short and compact, others tall and open, depending on the variety. In contrast, the Lowbush varieties form a dense ground cover that spreads by rhizomes underground. Lowbush varieties tend to be low growing plants, limited to 2 to 3 feet in height. In contrast, Highbush blueberries commonly grow up to 10 feet tall and can reach up to 23 feet in height.
All varieties of Northern Highbush and most Southern Highbush blueberries are self-pollinating, but will produce better crops if two varieties are planted together. Not all Lowbush varieties are self-fertile. All blueberries require insect pollination, usually accomplished by native bees. Commercial growers often bring in additional bee hives to ensure adequate pollination.
Lowbush varieties can be a challenge for home gardeners because they require attention to soil pH and extra weeding to establish. They need an acidic soil, preferably between 4.3 and 5.0. Because the plants spread in a dense mat, controlling them also may be an issue. Once established, Lowbush varieties need less maintenance than Highbush varieties. In contrast, Highbush varieties are easier to establish, but need regular pruning to keep them at a manageable height, while Lowbush varieties only need cutting back every 2 to 3 years to rejuvenate the plants.
With good care, all varieties yield a good crop of highly nutritious berries. They are highly valued for their antioxidant content and overall nutrition. Wild Lowbush varieties produce smaller berries with a distinctive "wild" flavor that many people prefer.