Blueberries will keep without sugar and taste like the fresh fruit when used in puddings, pies and shortcakes. If preferred sweet, allow one-half cupful of sugar to two pints of berries, excepting in the case of swamp berries, when one cupful of sugar is none too much.
In canning without sugar, pick over and wash the berries, drain, then pack in jars, filling as full as possible. Pass a silver knife around the sides to help them settle into place. Pour boiling water over the berries, going over and adding more boiling water as the fruit settles and absorbs the water. When filled to running over, screw on the covers to make air-tight and keep in a cool, dark place.