Combine the sauvignon blanc, rum, nectar, Lemongrass Simple Syrup, lemons, oranges, mint and passion fruit if desired in a pitcher. Cover and refrigerate for at least 2 hours and up to 24 hours.
Combine 1 cup water and the sugar in a small saucepan. Hit the stalks with the back of a knife to lightly bruise and help release the flavor. Add the stalks to the pan and bring to a boil over high heat. Cook until the sugar is completely dissolved. Remove from the heat, cover and refrigerate for at least 1 hour and up to 48 hours to let the flavor develop. Strain before using.