Wash, pit, and dice the peaches. Combine peaches, granulated sugar, water, and lemon juice in a medium saucepan over medium heat and simmer for 10-15 minutes.

Remove from heat and let cool slightly. Mash peaches and strain through a fine sieve to create a smooth puree.

In another saucepan, combine sugar and water for the simple syrup. Heat until sugar dissolves, about 5 minutes, and let cool.

Juice lemons to obtain 1.5 cups of juice. Combine with the cooled simple syrup in a large pitcher.

Mix the peach puree with the lemonade base and gradually add cold water to reach desired strength.

Refrigerate for at least 30 minutes, then serve over ice and garnish with peach slices, lemon wheels, and mint.