To prepare simple syrup, combine sugar and water in a small saucepan over medium heat and cook, stirring occasionally, until sugar is dissolved. Remove from heat and add 1 cup blueberries. Steep for 10 minutes, then use the back of the spoon to press on the berries to release their juices and flavor. Strain out the berries and allow syrup to cool to room temperature before proceeding.
To prepare pitcher cocktail, combine Sauvignon blanc, blueberry simple syrup, sparkling water, peaches, blueberries, and basil in a large pitcher. Stir to combine. Add ice before serving and stir again.