Behold the Boreal Blueberry

Boreal blueberry looks similar to Acadia’s typical lowbush blueberry, but has shorter stems, narrower leaves, and smaller flowers that appear 10 to 20 days earlier.

Photo by Catherine Schmitt, Schoodic Institute

The blueberry is a common and popular plant in Acadia. Most are the “lowbush” species, Vaccinium angustifolium, found on sandy and rocky ground, next to lakes and wetlands, along sunny trails, and on mountaintops. On the highest summits grows a similar species, boreal blueberry, Vaccinium boreale, also called northern blueberry, sweet hurts, and alpine blueberry.

A freeze-tolerant shrub more common to the north, boreal blueberry and other boreal plants are fragments of the tundra that once covered the landscape at the end of the most recent Ice Age. They persist in cold, windblown refugia on summits and coastal edges, on alpine ridges and tablelands of Mount Katahdin, the White Mountains, and the Adirondacks, places that are thousands of feet higher in elevation than Acadia.

Because of its rarity, boreal blueberry is considered a species of special concern by the State of Maine, ranked as S2, imperiled: “At high risk of extirpation in the jurisdiction due to restricted range, few populations or occurrences, steep declines, severe threats, or other factors.” Boreal blueberry is one of 25 rare, threatened, and endangered plant species in Acadia.

Botanists surveyed populations of boreal blueberry on Sargent Mountain and Cadillac Mountain in 1998. Five years later, members of the Garden Club of Mount Desert began monitoring boreal blueberry as part of Partners for Plants, a program of the Garden Club of America. Every year, Partners for Plants volunteers visit fixed plots established on Cadillac Mountain, documenting boreal blueberry presence, growth, and condition.

The future of boreal plants is uncertain as temperatures warm and precipitation patterns shift, and increasing numbers of visitors contribute to trampling and erosion. Continued monitoring is essential for informing management, and protecting these plants is one of the motivations for ongoing experiments to learn how best to restore summit vegetation.

Visitors can help protect boreal blueberry by staying on established trails, not stepping on plants, and contributing observations of blueberries to iNaturalist. Boreal blueberry looks a lot like common lowbush blueberry, and grows in similar dry soil. For a long time, scientists considered boreal blueberry a variant. In the 1950s, it was determined to be a separate species. Boreal blueberry can be distinguished by its shorter, more compact and branched growth, narrower leaves, and smaller flowers that appear ten to twenty days earlier, often before the plants have fully leafed out. Narrow leaves alone are not enough to identify boreal blueberry, since lowbush blueberry can also have slender leaves.

When photographing, try to capture any flowers and fruit as well as leaves. Note the height of the plant; if berries are dull, waxy, or glossy, and if possible document other plants, moss, and lichen growing alongside the blueberry, such as three-toothed cinquefoil, mountain cranberry, and Cladonia lichens.

The presence of boreal blueberry on Cadillac Mountain, one of the most-visited destinations in Acadia, shows that people and such rare plants can co-exist. It also means visitors have the opportunity to experience the landscape of a colder world.

Sources

Fritsch, P.W., A.A. Crowl, H. Ashrafi, and P.S. Manos. 2024. Systematics and evolution of Vaccinium Sect. Cyanococcus (Ericaceae): Progress and prospects. Rhodora 124(998-9): 301-332.

Hall, I.V., and L.E. Aalders. 1961. Cytotaxonomy of lowbush blueberries in Eastern Canada. American Journal of Botany 48(3): 199-201.

Vander Kloet, S.P., and T.S. Avery. 2010. Vaccinium on the edge. Edinburgh Journal of Botany 67(1): 7–24.

https://www.maine.gov/dacf/mnap/features/vacbor.htm

https://gobotany.nativeplanttrust.org/species/vaccinium/boreale/

https://www.gardenclubofmountdesert.org/new-and-noteworthy/partners-for-plants