Strawberry Rhubarb Lemonade

In a saucepan stir together the water, the rhubarb, the sugar, 2 strips of the zest, and the vanilla, bring the mixture to a boil, stirring until the sugar is dissolved, and simmer it, covered, for 8 minutes. Stir in 1 cup of the strawberries and boil the mixture, covered, for 2 minutes. Let the mixture cool and strain it through a coarse sieve set over a pitcher, pressing hard on the solids. Stir in the remaining 1 cup strawberries and the lemon juice, divide the lemonade among stemmed glasses filled with ice cubes, and garnish each glass with some of the additional zest.