1. In a saucepan, combine sugar, water and 4 sprigs rosemary. Simmer until sugar has dissolved, stirring occasionally with a wooden spoon. Remove pan from heat and allow to cool.
2. Pour syrup over chopped strawberries and let sit at room temperature for an hour.
3. Discard rosemary sprigs, and purée strawberries and syrup in blender. Strain mixture through a mesh sieve. You should have about 1 cup strawberry purée.
4. Fill 6 tumblers with ice. Into each pour 2 ounces strawberry purée, 4 ounces rosé wine, and 1/2 ounce of Aperol. Stir. Top each cocktail with 1 ounce club soda. Garnish each with a sprig of rosemary.
Note: Leftover strawberry purée is delicious swirled into plain Greek yogurt for breakfast.