Use a paring knife to slice the peel off a lemon, set aside with fresh rosemary sprigs.
Add 1 1/2 cups of sugar and water to a small saucepan and bring to a boil. Add in lemon peel and rosemary sprigs and continue boiling for a few minutes, until mixture is clear.
Pour syrup mixture into a container to cool slightly.
Place tea bag in the bottom of a large pitcher and pour boiling water over the top. Let tea steep for 5 minutes, then remove tea bag (remember, don't squeeze!).
Pour in cooled syrup mixture (through a strainer to catch the lemon peel and rosemary), add cold water and stir to combine thoroughly.
Place pitcher in refrigerator to cool.
Serve cold, over ice, and garnished with a sprig of rosemary and lemon wedge, if desired.