Small clusters of nodding flowers are produced from either lateral or terminal shoots, often in succession along individual branches. These flowers are about 1/3" (8 mm.) in length. Each flower consists of a tubular corolla, a short calyx, 10 included stamens, and a pistil with a single style. The corolla is white to pinkish white with 5 short broad teeth along its outer rim that are recurved. The calyx is light green and glabrous with 5 short broad teeth. The calyx is much shorter than the corolla. The pedicels of the flowers are light green to red and either glabrous or finely short-pubescent; they are up to ½" in length. The pedicel bases have conspicuous bracts that are light green to red, elliptic to ovate in shape, and glabrous. The blooming period occurs during late spring for about 2 weeks. Fertile flowers are replaced globoid berries that become about 1/3" (8 mm.) across at maturity. Mature berries are blue to blue-black with a white bloom; their interiors are sweet to sweet-tart and juicy, containing many tiny seeds. The root system is woody and spreading. This shrub spreads by reseeding itself. The deciduous leaves turn red during the autumn.
Cultivation: The preference is full or partial sun, wet to moist conditions, and an acidic soil that is peaty or sandy.
Range & Habitats: The native High-Bush Blueberry occurs in NE Illinois, where it is rare and state-listed as 'endangered' (see Distribution Map). Illinois lies along the western range-limit of this species. Habitats include forested bogs, tall shrub bogs, borders of lakes and streams, and sandy swamps. Trees that are associated with this shrub include the native Tamarack (Larix decidua), Red Maple (Acer rubrum), and Yellow Birch (Betula lutea). In Illinois, this shrub is found in high quality wetland habitats, where it benefits from relatively uncommon wildfires during periods of severe drought.
Faunal Associations: The flowers are cross-pollinated by various bees, including honeybees, bumblebees, and Andrenid bees. These insects obtain nectar and/or pollen from the flowers. Other insects feed on High-Bush Blueberry and other blueberries in a more destructive manner. The caterpillars of several butterflies feed on either the flowers or leaves of these shrubs; these species include Callophrys augustinus (Brown Elfin), Callophrys henrici (Henry's Elfin), Colias interior (Pink-Edged Sulfur), Polygonia faunus (Green Comma), and Satyrium liparops strigosum (Striped Hairstreak). In addition, the caterpillars of such moths as Acronicta tritona (Triton Dagger Moth), Catocala gracilis (Graceful Underwing), Sphinx canadensis (Canadian Sphinx), and Xestia normaniana (Norman's Dart) feed on these shrubs; see the Moth Table for a more complete listing of these species.
Other insect feeders include the beetle larvae of Oberea myops (Rhododendron Stem Borer) and Oberea tripunctata (Dogwood Twig Borer), the leaf beetles Altica sylvia and Neochlamisus cribripennis, the larvae of Dasineura oxycoccana (Blueberry Gall Midge) and Rhagoletis mendax (Blueberry Fruit Fly), Clastoptera proteus (Dogwood Spittlebug) and Clastoptera saintcyri (Heath Spittlebug), the leafhoppers Limotettix vaccinii and Scaphytopius magdalensis, and Mesolecanium nigrofasciatum (Terrapin Scale). Many vertebrate animals feed on the berries of these shrubs. Birds that feed on the berries include the Ruffed Grouse, Eastern Bluebird, Catbird, Veery, Wood Thrush, and Sandhill Crane (see the Bird Table for a more complete listing of these species). Blueberry fruits are also eaten by many mammals, including the Black Bear, Red Fox, Raccoon, Eastern Skunk, White-Footed Mouse, and Jumping Mouse. The twigs are browsed by the White-Tailed Deer and Cottontail Rabbit during the winter. The value of this shrub to wildlife is high.
Photographic Location: A garden at the Arboretum of the University of Illinois in Urbana, Illinois, and a sandy swamp at Cowles Bog in NW Indiana.
Comments: Because High-Bush Blueberry is somewhat variable across its range, it has been divided by taxonomists into several species, subspecies, and varieties in the past. However, because these distinctions intergrade with each other in the field, they have been united into a single species, Vaccinium corymbosum. High-Bush Blueberry is a taller shrub than other species of blueberries that occur in Illinois and it prefers habitats that are more moist. Because of the size, abundance, and excellent flavor of its berries, this shrub is an important agricultural crop in many areas of the United States. For this purpose, many cultivars have been developed.