Slice on the the rhubarb stalks into 1 inch pieces. Bring water, sugar or honey and sliced rhubarb to a simmer and cook just until sugar is dissolved (about 2-3 minutes). Pour the simple syrup into a pitcher along with 4 cups of water and the lime juice. Refrigerate for 1 hour or until ready to serve. Serve the limeade garnished with mint, extra lime slices, and use the extra stalk of rhubarb (sliced into 4 equal parts) as a stir stick of sorts.