In a small saucepan, heat 2 cups water and sugar over medium-high heat; bring just to a boil, whisking if necessary to dissolve sugar. Stir in rosemary; remove from heat, and let cool to room temperature. Cover and refrigerate until ready to use.
In a large saucepan, bring lemons and remaining 12 cups water to a boil over medium-high heat. Add tea bags, and let stand for 15 minutes.
Discard tea bags, and transfer tea to a serving pitcher. Strain reserved rosemary syrup, discarding solids, and sweeten tea to taste. Serve over ice, and garnish with lemon and rosemary, if desired.
Notes
*We used Luzianne® Family Size Iced Tea Bags.
Recipe by Louisiana Cookin' at https://louisianacookin.com/lemon-rosemary-sweet-iced-tea/