In a medium saucepan, bring sugar, 1 cup water, rosemary, and ginger to a boil. Remove from heat and let steep 30 minutes. Strain through a fine-mesh sieve, discarding solids; set aside.
In a large punch bowl, stir together simple syrup, sparkling water, and ginger ale. Carefully add sherbet scoops. Garnish with lime, orange, and rosemary, if desired.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/citrus-rosemary-punch-recipe/