In a blender, combine the 2 cups berries and the water. Cover and blend until mixture is pureed. Press mixture through a fine-mesh sieve set over a bowl, forcing puree through with back of spoon or rubber spatula; discard seeds. Pour puree mixture into a 2-quart pitcher. Stir in lemonade concentrate and sugar, stirring until sugar dissolves. Chill lemonade until ready to serve.

Before serving, stir lemonade. Slowly pour club soda into lemonade in pitcher. Pour into ice-filled glasses and serve. Garnish each glass with lemon slices and, if you like, additional fresh berries. Makes 10 (6-ounce) servings.