Identify them by their size.
I spotted them at the Tompkins Square market Sunday: bush blueberries of the type that grow wild in northern lakeside and mountainous regions. They are about half the diameter of regular commercial blueberries, and are more strongly flavored. Some berries are almost unbearably sweet, while others pucker the mouth.
Really, while regular commercial blueberries taste good, these are really distinctive. Used in a tart, pie, or shortcake, they’re unbeatable.
I found them selling for $4 for a half-pint at Stannard Farms, an eclectic agricultural operation from Washington County, an area northeast of Albany along the Vermont border. They will be in the Columbia Greenmarket this Thursday; pray Stannard still has them. I’ve also found them in previous years at the stands of Catskillian berry farmers, so keep your eyes open, especially at Union Square and Fort Greene.