01 - Combine sugar and 1/2 cup of water in a small saucepan. Heat over medium, stirring constantly, until the sugar fully dissolves. Remove from heat and set aside to cool.
02 - Add the sliced peaches, freshly squeezed lemon juice, and lemon zest to a blender. Purée on high until completely smooth.
03 - Pour the peach purée through a fine-mesh sieve into a large pitcher, pressing with a spatula to extract as much liquid as possible. Discard the solids.
04 - Add the cooled simple syrup and 3 cups of cold water to the pitcher. Stir thoroughly until well combined.
05 - Taste the lemonade and adjust sweetness or tartness by adding more sugar or lemon juice as needed.
06 - Refrigerate for at least 1 hour before serving, or serve immediately over ice. Garnish each glass with fresh mint, peach slices, and lemon wheels.