The following is an excerpt from Buddleia: Butterfly Bush Extraordinaire by Claire Hagen Dole:
With a name like butterfly bush, you might expect a plant to be attractive to butterflies. In fact, it’s more than attractive; it’s a magnet for all the butterflies who pass through your garden seeking nectar. Many butterfly gardeners plan their garden around Buddleia (pronounced BUD-lee-ah), a genus that includes over 100 species and cultivars. Also called summer lilac, the medium- to large-sized shrubs can anchor a perennial bed or form a hedge. You’ll be happier with Buddleia if you accept its growth habit, which is not neat and tidy. 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. But wait till you see the bush covered with fritillaries and tortoiseshells! Even a large swallowtail can land on the cluster, to sip from the many individual blooms. Butterflies and bees will flock to the honey-scented blossoms, whose dilute nectar is sweetest in midday sun. Near a path or patio, the shrub provides delightful fragrance for you, too.