Bog blueberry is a pink-flowered, blue-berried shrub in the heath family (Ericaceae) that is remarkably common – and found in nearly all habitats where plants grow in Denali. Vaccinium uliginosum is particularly abundant in open upland forest and shrub tundra in the subalpine zone across the northern tier of the park, but is nearly ubiquitous. Plants often grow low to the ground, much branched, or erect, up to 60 cm tall. Bog blueberry grows from rhizomes, often forming large thickets. The leaves are alternately arranged, obovate or elliptic in outline, light green in color, 6-25 mm long, with entire margins. Flowers grow on terminal branches, four or five in a cluster. The peduncles are red, above a small calyx, divided into five red teeth. Flowers are pink and urn-shaped, 3-4 mm long, with four or five small upturned white lobes at the tip. The berries are round and juicy, 5-8 mm wide, blue-black with a paler bloom, and bright purple flesh. Even lacking pink urn-shaped flowers or blueberries, this shrub can be recognized by its pale green, entire-margined obovate leaves.
Blueberry flowers in June, and fruits in August and September. Berries are green and hard when unripe, becoming blue. The shrubs are perennial, with deciduous leaves. Roots grow at two times in the year, during spring and fall.
Blueberry is monoecious with bisexual flowers. Flowers are nectar producing and insect pollinated, mainly by bees. Flowers can also self-pollinate, though out-crossed fruits contain more seeds (Jacquemart and Thompson 1996). Fruits are eaten by mammals and birds, dispersing seed in their scat. Seeds can be viable for at least 6 years (Vander Kloet and Hill 1994). Seeds have a short dormancy period, and the kind and length of stratification needed has varied by study. Seeds germinate at temperatures above 15 degrees. There are on average 13 viable seeds per berry (Jacquemart 1996). The plants also spread vegetatively from their rhizomes, forming dense thickets. This appears to be the main mode of reproduction, as few seedlings are found (Jacquemart 1996).
V. uliginosum berries have a sweet, tart flavor and are widely used for food. Native peoples picked them and mixed them with animal fat for long term storage. Currently they are eaten fresh, frozen, or turned into preserves. Bog blueberries are commercially harvested in Alaska, and turned into berry products or dietary supplements, due to the high anti-oxidants in wild blueberries.
Vaccinium uliginosum is a circumpolar species with a widespread distribution. In North America, this species range reaches the western United States, southwards to California, Wyoming, Colorado and Utah. Its range covers Canada to the eastern seaboard, and reaches the northern edge of New England. Vaccinium uliginosum occurs throughout Alaska. This is the most common and widespread plant species in Denali, particularly abundant on the north side of the park, and in the subalpine zone, but excluded from only the wettest and driest sites in the park.
This species'slope frequency peaks at 4-12 degrees, still high for other categories. Highest cover at 4-12 degree slopes, slightly more dramatic disparity. Equally common by aspect, but more cover on south slopes. Cover highest at the subalpine (500-900 m), close to 15% at 500-700 m. least frequent at 300-500 meters.