Peaches and blackberries sweeten iced tea.
Put tea bags and the boiling water in a medium saucepan or heatproof bowl. Let stand 5 minutes. Discard tea bags. Transfer tea to a large pitcher.
Cut 2 of the peaches into 8 wedges each. Add sliced peaches and the sugar to the tea. Stir tea until sugar has dissolved. Let cool completely.
Stir in peach nectar. Refrigerate tea until cold (or up to 1 week in an airtight container). Just before serving, remove peaches; discard. Cut remaining peaches into 8 wedges each. Add peaches and blackberries to the tea. Serve over ice.