Rinse and pick over blueberries.
Combine water and sugar in a saucepan; heat to the boiling point.
Place 1 pint of blueberries in the bowl of a food processor.
Process, turning the machine on and off about 4 times, until berries are coarsely pureed.
Add pureed blueberries to the sugar syrup; add lemon juice; bring back to a boil.
Cook about 2 minutes more.
Add remaining pint of whole berries, reserving a few for decoration.