It’s Blueberry Season!

By Karen C. Beattie

Summer is in full swing here on Nantucket – the beaches are packed, the restaurants and shops in town are at their busiest and the bike paths are congested. If you are looking for an alternative to these more common summer activities and want to be a true “Nantucket Locavore,” you are in luck- late July and early August is native blueberry season!

Blueberries are members of the Ericaceae, or Heath family. This diverse group of flowering plants tend to prefer acidic environments and are often associated with damp soils and wetlands. In order to thrive in such infertile soil conditions, many members of the Heath family have mycorrhizal fungi associated with their root systems, where the fungi provides the plant with increased ability to break down and absorb nutrients, while the plant provides the fungi with carbohydrate “food” produced during photosynthesis. Because Nantucket has sandy, nutrient poor and acidic soils, other species in the Heath family are also common here, including black huckleberry, cranberry, dangleberry, wintergreen, swamp azalea, mayflower, leatherleaf, bearberry and sheep laurel.

Blueberries are deciduous shrubs with elliptical, short-stalked leaves and zig-zagged stems. They bear small white to pale pink bell-shaped flowers in drooping clusters in late spring. Each one of these flowers needs to be visited by a pollinating insect in order for a berry to be produced in late summer. Blueberries are not just enjoyed by humans, they are also a very important source of food for many species of birds and other wildlife, and the stems and leaves are browsed upon by deer and rabbits. Blueberry bushes turn a dramatic shade of vibrant red in the fall before dropping their leaves, and therefore are an excellent, native, low-maintenance choice for landscaping projects.

Nantucket’s vast open space properties host not just one, but four species of native blueberries – two species of highbush blueberries and two species of lowbush blueberries. The one that most people are familiar with is highbush blueberry (Vaccinium corymbosum). This is the native species from which most commercial blueberry cultivars originated. While lowbush blueberries grow low to the ground in sunny, dry uplands, highbush blueberries occur primarily in moist environments such as swamps, bogs, pond shores and damp woodlands. These species can grow up to 12 feet tall, which makes berry picking relatively easy – except for the upper branches, which you can leave for the birds. Another very similar species of highbush blueberry, black highbush blueberry (Vaccinium fuscatum), lacks the waxy outer coating (called a “bloom”) that makes other blueberries appear light blue – but the dark shiny fruit are just as tasty. Look for both highbush blueberry species in the woods and wetland edges at Squam Swamp, Squam Farm, Windswept Cranberry Bog, Sanford Farm and Ram Pasture, and along many of the kettlehole pond shores of the Middle Moors.

Our other two blueberry species – common lowbush blueberry (Vaccinium angustifolium) and sweet lowbush blueberry (Vaccinium pallidum) – are difficult to distinguish. Common lowbush blueberry has small, dark green shiny leaves, while sweet lowbush blueberry has slightly larger, more leathery leaves with pale green undersides. As their names imply, they only grow 1-2 feet in height and require a little bit of strain on the back to pick. Lowbush blueberries occur in open, full sun locations and grow clonally, with an individual plant consisting of many stems connected by a vast underground root system. Although smaller and less fleshy than highbush berries, many wild blueberry connoisseurs think that lowbush berries are the sweetest and best tasting. Both species of lowbush blueberries are common in the heathlands and grasslands along the south shore of the island at Madequecham, Smooth Hummocks, Ram Pasture and Head of the Plains, as well as some of the more open heathland habitats in the vicinity of Altar Rock in the Middle Moors.

Nantucket’s vast conservation lands are open to the public for passive recreational uses. In most cases, the old adage to “take only pictures and leave only footprints” is the preferred policy of open space property managers. However, blueberry picking by individuals (in limited quantities for non-commercial purposes) is allowed, so feel free to indulge – as long as you leave some for other blueberry pickers and for the birds! A word of caution: whenever you are foraging for wild foods, it is always a good idea to be 100 percent certain that you have correctly identified what you are picking and eating.

All blueberries are fire-adapted. Like many other Heath species, they contain volatile oils in their leaves and stems that burn readily and often completely, but quickly regenerate from their clonal root systems during the following growing season. Commercial blueberry growers regularly burn their blueberry fields to boost crop yields, as flower and fruit production increases significantly the second season following a burn. Prescribed fire is often used by the island’s conservation groups, particularly the Nantucket Land Bank, in Nantucket’s sandplain grassland and heathland habitats to control the encroachment of tall woody shrubs and trees and stimulate the growth of grasses and native wildflowers. This management practice is also very beneficial to lowbush blueberry populations- so if you want to know where the best blueberries will be, start keeping track of where prescribed burning has taken place and return to that spot a couple seasons later for the best crop!

*Please note, this blog post was originally published in The Inquirer and Mirror on August 3, 2017 in the article series called Island Ecology. The Foundation’s Science staff regularly contribute to our local newspaper and reprint the articles here the following week.

The Nantucket Conservation Foundation is a private, non-profit land trust that depends contributions from our members to support our science projects, conservation property acquisitions and land management efforts. If you are not already a member, please join us!  www.nantucketconservation.org