You can use frozen blueberries, it will make the color of the bread run significantly more. If you can gently rinse and dry the blueberries you can help prevent excess running of the color. Just try to minimize how much you stir the blueberries.u003cbr/u003eu003cbr/u003eIf using frozen blueberries you can try sprinkling them in layers over the batter and spoon the batter into the loaf pan rather than pouring them all in to minimize color bleeding.