In a small saucepan, gently heat 1 cup of water with the culinary lavender buds. Simmer for about 5 minutes, then remove from heat and let steep for 15-20 minutes. Strain the lavender-infused water through a fine-mesh sieve, discarding the buds. Let cool completely.
In a large pitcher, combine the fresh lemon juice, agave nectar, cream of coconut, and the remaining 3 cups of water.
Add the cooled lavender-infused water to the pitcher and stir well to combine.
Refrigerate for at least 30 minutes to allow the flavors to meld.
Serve over ice, garnished with fresh lavender sprigs and lemon slices.
Notes
Adjust sweetness and lavender intensity to your preference. For a stronger lavender flavor, steep the buds longer or use more buds.