This plant is commonly called butterfly bush because of the hordes of butterflies (and bees) that are attracted to its wonderfully fragrant flowers. Many butterfly gardeners plan their garden around Buddleia (pronounced BUD-lee-ah), a genus that includes over 100 species and cultivars. The medium- to large-sized shrubs can anchor a perennial bed or form a hedge. Its narrow branches support lilac-like clusters of blossoms a foot or two in length, with side branches and blossoms. After a rainfall, the flower-laden branches of some species can droop all over your flower bed. You'll want to allow at least six feet between bushes to keep some semblance of neatness.