Add 1 cup water and 3/4 cup sugar to a small saucepan. Warm over medium heat, stirring until the sugar completely dissolves.
Remove the saucepan from the heat. Stir in the dried culinary lavender, cover, and let steep for 10 minutes.
Strain the syrup through a fine mesh strainer, discard the lavender buds, and allow the syrup to cool completely.
In a large pitcher, combine the fresh lemon juice, 3 cups cold water, and about 3/4 cup of the cooled lavender syrup. Stir well.
Taste the lemonade and adjust by adding more syrup for sweetness, more lemon juice for tartness, or more cold water for a lighter flavor.
Chill for 30 minutes. Serve over ice and garnish with lemon slices, fresh mint, berries, or a food-safe lavender sprig if desired.