Delicious raspberries (Rubus spp.) are fairly simple to grow, and unlike many other types of fruit, will produce well in both full sun and dappled shade. When growing raspberries in North Carolia, however, some considerations beyond simply the amount of sunlight must be taken into account.
Raspberries grow best in mild areas with cool winters. Their U.S. Department of Agriculture plant hardiness range varies by type, but they generally do well between USDA zones 4 and 8, roughly speaking. Since North Carolina’s hardiness zones range from 6b through 8a, it is an acceptable climate for growing raspberries. Although raspberries sometimes have difficulty with North Carolina’s hot, humid summers, making the mountains and foothills of the western part of the state the most amenable to raspberry production. According to North Carolina State University, the varieties “Dormanred” and “Southland” show good tolerance to extreme heat as sometimes encountered in the state's piedmont region, while the former also has less need for chilling, making it an appropriate choice in coastal regions.
Problems with Shade
Raspberries produce best in full sunlight in North Carolina, as elsewhere. Although raspberries may grow in some shade, deep shade doesn’t usually work. For one thing, raspberries often produce fruit underneath leaves and on the inner areas of canes; in shade, no sunlight will reach inside the plants, limiting fruiting capacity. Shade can decrease temperatures, subjecting raspberries to severe cold in wintertime, though this would be less problematical in the piedmont and coastal areas, with their milder winter temperatures.
Site Selection and Shade Reduction
Growing healthy raspberries depends on choosing the best variety for your region and microclimate, which varies throughout the state, and on good site selection beforehand. Prepare your raspberry bed away from significant sources of overhead shade: trees, structures, and anything else that might prevent the bed from soaking in sunlight for several hours per day. Thin canes every year in order to remove the dead ones, reducing the chance of other canes being unnecessarily shaded out.
Raspberries grow best when given some kind of support system. Except for dwarf varieties, which can be much shorter, raspberries are usually 4 to 5 feet tall, and very thin. This means they can flop over easily, so growing them along a trellis or wire fence helps them stay upright. It also helps sunlight penetrate to the leaves all along the stem, which produces better fruiting and prevents moisture from sticking around and encouraging rot or fungus.