First, we took their berries, and now as their leaves color, we steal them, too. Fresh or dried, blueberry leaves make great tea that is beneficial for blood pressure, arthritis, and all sorts of inflamation.
The medicinal properties of the leaves are enhanced and concentrated as the leaves change color in the fall. That is the best time to harvest them for steeping or drying. A heaping teaspoon full of broken leaves will make a good cup of tea.