1. Place basil and one cup of blueberries into large pitcher. Gently muddle and set aside.
2. Combine lemon juice, one cup water, honey, and remaining blueberries in saucepan over medium-high heat. Bring to low boil, stirring to dissolve honey. Once blueberries have released their juice and color, pour mix through fine mesh strainer into prepared pitcher.
3. Pour remaining water into the pitcher along with handful of ice. Add muddled blueberry-basil mixture. Stir to combine. Serve cold, garnished with lemon slices if desired.