Bring all of the above to a boil in a saucepan, stirring occasionally. Reduce heat to low. Simmer on low for 10 minutes. Let cool. Double strain into a glass jar or bottle. Refrigerate.
Tip: If you want your herbal syrups to be more pungent, put healthy amounts of plucked leaves into the saucepan with equal parts sugar and water. If you prefer a more subtle flavor, you can adjust the recipes by using a smaller quantity of herbs according to your taste. One rule to keep in mind when muddling herbs directly into cocktails or cooking them into syrups is not to include the plant stem. It adds an unpleasant bitterness that can be avoided by using only the leaves and flowers of an edible plant.
Try with: Lavender Gin Sour
These recipes and notes are from a wonderful new book called Edible Cocktails: From Garden to Glass—Seasonal Cocktails with a Fresh Twist by Natalie Bovis, the Liquid Muse, F+W Media, April 2012.