A fragrant and lovely shrub long popular for attracting both hummingbirds and butterflies, Buddleia davidii (the butterfly bush, also known as summer lilac) was first imported from China as an ornamental planting. It has, however, an aggressive side, like kudzu, though not so pronounced. Thanks to its profusion of seeds so readily carried by birds, deer, dogs, and other animals, the state of Washington, for example, is considering listing the butterfly bush as an invasive weed.

This move would put it up alongside English ivy and Scottish broom. The Class C identification--specifically, noxious weed rating--does not entirely outlaw the plant in question from being sold or grown. It does, however, indicate that it is a significant threat to a native habitat or habitats. In the case of Buddleia davidii, this means the wetlands, especially along creeks and streams and rivers.

Controlling the butterfly bushes you do have is primarily a matter of pruning and deadheading through its long growing season. The double-win is that this practice enhances both the blooms themselves and the growing season. To further minimize the threat of spreading viable Buddleia davidii seeds, the deadheaded flowers should not be composted, of course, but bagged with other household trash.

Butterfly Bushes in Your Garden

Buddleia comes in a wide variety of colors and shapes, far more than any easy short list can convey. Location and weather zone, of course, have much to do with what thrives where, and nursery catalogs and websites will be quite specific. Among the popular ones are Dartmoor (hybrid, a blackberry scent, narrow leaves, pink/purple, about six feet), the asiatica (white flowers, great cut flower, 15 feet), Opera (hybrid, bright fuchsia, six feet), Royal Red (maroon flowers that glow in sunshine, six feet, award winner), and the Purple Prince (very fragrant, upright, about 10 feet tall).