For lemon syrup, place first 4 ingredients in a small saucepan; bring to a boil, stirring occasionally. Remove from heat; let stand, covered, 10 minutes. Remove rosemary and lemon zest. Stir in lemon juice; cool completely., Place blueberries and sugar in another saucepan; cook and stir over medium heat until berries pop, 5-7 minutes. Cool completely., Add whipped topping to the lemon syrup, whisking to blend. Transfer half the mixture to a pastry bag. Pipe into molds. Layer with blueberries. Pipe the remaining whipped topping mixture over top. Close molds with holders. If using paper cups, top with foil and insert sticks through foil., Freeze until firm, about 4 hours. To serve, dip pop molds briefly in warm water before removing.