Hillside Blueberry
Vaccinium pallidum
Heath family (Ericaceae)

Description: This is a deciduous shrub about -3' tall that branches occasionally. Young branches are initially green, but they later become yellowish green and more or less covered with small warty dots. Young branches are usually glabrous, but sometimes they are slightly pubescent. Older branches become woody and vary in color from red to yellowish brown; on the trunk and very old branches, the bark becomes shredded. Alternate leaves occur along new branches. The blades of these leaves are -2" long and -1" across; they are oval, ovate, obovate, or broadly elliptic in shape, and their margins are smooth or minutely toothed toward the tips of the blades. The upper surface of the leaf blades is medium green or yellowish green and glabrous (sometimes with reddish tints in bright sunlight), while the lower surface is pale green, glabrous, and sometimes glaucous. Less often, the lower surface of the leaf blades may be slightly pubescent. The petioles are short and slender.

Raceme-like clusters of flowers develop from second-year branches. The pedicels of the flowers are light green and glabrous. Each flower (up to 1/3" or 8 mm. in length) is longer than it is wide, consisting of a tubular corolla with 5 tiny recurved lobes, a short light green calyx with 5 broad teeth, 10 inserted stamens, and a pistil with a single style. The corolla is somewhat constricted toward its outer rim and its exterior is greenish white, pink-tinted cream, or red. The blooming period occurs from late spring to early summer and lasts about 3 weeks. The flowers are replaced by globoid berries about " across that are initially green, but they later become dark blue with a whitish bloom. The berries become mature during mid- to late summer; they are juicy and sweet, containing 8-20 tiny seeds that are less than 1.5 mm. in length. The woody root system is branched and shallow, forming underground runners that can produce clonal offsets. At favorable sites, colonies of clonal plants are often formed. The leaves become red to dark red during the autumn before they fall to the ground.

Cultivation: The preference is partial sun, mesic to dry conditions, and an acidic soil containing sandy or rocky material.

Range & Habitat: Hillside Blueberry is occasional in northern Illinois, southern Illinois, and sandy areas along the Illinois River in central Illinois. Elsewhere in the state, it is rare or absent (see Distribution Map). Habitats include upland rocky forests, thinly wooded bluffs and rocky hillsides, sandy forests and sandy savannas, openings in sandy forests, sandstone cliffs and glades, sandy roadside embankments, sandy ditches, and abandoned sandy fields. Hillside Blueberry is often found in fire-adapted habitats because it is able to resprout from its underground runners. Dominant trees in these habitats are either oaks or pines.

Faunal Associations: The flowers are cross-pollinated by honeybees, bumblebees, and Andrenid bees. These bees suck nectar from the flowers and, to a lesser extent, collect pollen. Various insects eat the leaves and other parts of blueberries (Vaccinium spp.). These species include the caterpillars of the butterflies Callophrys henrici (Henry's Elfin), Callophrys augustinus (Brown Elfin), and Colias interior (Pink-Edged Sulfur). The caterpillars of Hemaris gracilis (Graceful Clearwing), Sphinx canadensis (Canadian Sphinx), and other moths also use blueberry shrubs as a food source (see Moth Table). Other insect feeders include Oberea myops (Rhododendron Stem Borer), Melanoplus fasciatus (Huckleberry Spur-Throated Grasshopper), Altica sylvia (Blueberry Flea Beetle), Neochlamisus cribripennis (Blueberry Case Beetle), Tricholochmaea vaccinii (Blueberry Leaf Beetle), Dasineura cyanococci (Gall Fly sp.), Dasineura oxycoccana (Blueberry Gall Midge), Rhagoletis mendax (Blueberry Maggot Fruit Fly), Mesoleucanium nigrofasciatum (Terrapin Scale), Illinoia azaleae (Aphid sp.), and Clastoptera saintcyri (Heath Spittlebug). The species Acalitus vaccinii (Blueberry Bud Mite) forms galls on the flower buds. The edible berries are eaten by many upland gamebirds and songbirds (see Bird Table). Mammals that eat the berries include the Black Bear, Gray Fox, Red Fox, Striped Skunk, Opossum, Red Squirrel, Gray Squirrel, Fox Squirrel, Eastern Chipmunk, White-Footed Mouse, Woodland Deer Mouse, and Jumping Mouse. The berries are also eaten by Terrapene carolina (Eastern Box Turtle) and Clemmys insculpta (Wood Turtle). The leaves and twigs of blueberries are occasionally browsed by White-Tailed Deer and the Cottontail Rabbit. Colonies of Hillside Blueberry and other low-bush blueberries provide cover for many small animals in upland areas.

Photographic Location: An open sandy woodland near Bittersweet Farm in NW Ohio.

Comments: There is some variability in the shape of leaves, the hairiness of leaves and young stems, and the color of the flowers. As a result, different varieties of Hillside Blueberry have been described by some authors. In areas where their ranges overlap, this species is capable of hybridizing with the similar Vaccinium angustifolium (Northern Low-Bush Blueberry). This latter species tends to have more slender leaves than Hillside Blueberry, and they are usually more serrated along their margins. While the lower leaf surface of Hillside Blueberry is lighter (pale green) than the upper leaf surface, the lower and upper leaf surfaces of Northern Low-Bush Blueberry are about the same color (medium green). An obsolete scientific name of Hillside Blueberry is Vaccinium vacillans. Other common names of this species are Early Low-Bush Blueberry and Blue Ridge Blueberry.