This recipe for lavender sour syrup was featured in the Fall 1999 issue of Martha Stewart Weddings.
Bring sugar and 2 cups water to a boil in a saucepan over medium heat, and cook, stirring, until sugar has dissolved. Reduce heat to low and add lavender. Cover and let steep 15 minutes.
Strain mixture through a fine mesh sieve into a large pitcher. Add lemon juice to taste. Keep refrigerated until ready to use.