We're partial, of course, to our own selection of the Purple Coneflower, but we find real value in the popular Echinacea purpurea 'Magnus' variety, whose petals are an especially vibrant carmine-rose shade and are held almost horizontally, making a more open face than the shuttlecock shape of the species. Lovely with the blue wands of Perovskia, another stalwart of the late-summer garden.