Credit: Aislinn Sarnacki | BDN

This story was originally published in July 2019.

Maine’s wild blueberries are wilder than you might imagine. They proliferate in Maine, only because they are tenacious survivors.

Think about it. Not long ago — about 10,000 years or so — the state was covered by a mile of ice. Glaciers carried much of Maine’s topsoil out to sea, and pulverized the remaining rock into sand and gravel. The remnant soil was low in nutrients and strongly acidic. And the blueberries liked it.

Eventually, the forests returned, but the berries remained. Barely clinging to existence, they bided their time in the shade, waiting for a fire or other cataclysmic event to open the canopy and set them free. Today, some of Maine’s blueberry barrens go on for miles. But before you take them for granted, here are a few things that might surprise you.

Two-thirds of each plant lives underground. That’s why fields can be burned or mowed to suppress weeds, and the blueberries just bounce right back.

Blueberries spread underground. The barrens may look like a vast array of multiple plants, but a single plant can be the size of a football field. Every shoot and berry within that plant is genetically identical, a clone of its neighbors. Another plant can be growing adjacent to it, with a slightly different flavor. Look closely, and you may begin to see that one set of plants is just a little taller, or the berries are slightly bigger or a different color. Taste the difference. This variability is one reason Maine wild blueberries are far more delicious then their cultivated competitors.

Blueberries figured out how to beat the infertility of glacial soil, forming a symbiotic relationship with a particular fungus. The fungus is capable of extracting nutrients from sand, making them available to the blueberry. In return, the blueberry produces a sugar from the nutrients that it shares with the fungus. Both live happily ever after.

Blueberries like acidic soil, which is fortunate for us, because that’s what Maine has. They like it best when the soil is about as acidic as tomato juice.

Wild blueberries grow where they want to grow. They are hard to transplant. It’s possible to plant a seed and grow a seedling, or bury a cutting and hope for the best. But it may be years before the plant produces a mouthful of berries. Even an established blueberry plant extends its roots about an inch per year, which is why growers don’t plant new patches. Rather, they merely clear adjacent woodlands, liberating already established berries hidden among the trees. Cultivated blueberries are relatively easy to transplant, which is one reason why they are now grown all over the world, despite their weaker taste and lower nutritional value.

Cultivated blueberries are less flavorful than Maine wild blueberries, but that’s partially because of how they are handled. Most of the cultivated berries are grown for the fresh fruit market. They are typically picked before they are fully ripe, and it may take days to work their way through the transportation system. A fresh berry in the produce section may have been picked over a week ago. By contrast, over 90 percent of Maine wild blueberries are flash frozen at the peak of flavor within hours of harvest.

Americans tend to think bigger is better, which gives the cultivated berries a marketing advantage over Maine’s wild blueberries. Consumers don’t always realize that wild blueberries contain twice the antioxidants, that much of the flavor is in the skins, and that cultivated blueberries are larger in part because they contain more water.

Maine wild blueberries are the most pollinated crop in America, other than California almonds. Migrant honeybees actually have to struggle to reach into the blueberry’s downward-pointing, bell-shaped blossom. But our native bumblebees just hover up to the flower and buzz, knocking the pollen loose and onto themselves. When our fields yielded 1,000 pounds per acre, the bumblebees could handle the job alone. But growers and agricultural scientists have improved yields to over 5,000 pounds per acre, and the local pollinators need help.

You might be surprised to learn that growers have learned how to reduce the use of chemicals, through a system called integrated pest management. Fields are constantly monitored for pests, and many outbreaks are prevented merely by adjusting harvest dates and mowing schedules. Where more drastic measures are needed, a light treatment around the borders of a field can sometimes create a bug barrier across the entire field.

Maine blueberries. Yes, in fact, they are the best.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at He can be reached at