Butterflybush, Buddleja davidii is a shrub from China. It has long clusters of flowers, purple or rose, lavender or white. They attract butterflies, hence the common name.
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| butterflybush, Buddleja davidii |
Buddleja was named by Linnaeus in honor of Adam Buddle (lived about 1660-1715) a British clergyman and botanist. You will often see it spelled Buddleia, but Buddleja is the correct spelling of the scientific name because that is how Linnaeus spelled it. He used a now-obscure Latin spelling to tell us the i is long. In Latin they sometimes dragged an i below the line to show it was a "long i" which we see as a j. Pronounce the j as a long i, Bud lee a.
There are about 140 species of Buddleja, found in Asia, Africa, and North and South America. They are very diverse with flowers of many colors and shapes (see examples link). About 60 species are native to the Americas but only seven to North America, especially Texas. Most Buddleja species are called butterflybushes in English. (Some sources make that two words, butterfly bush, take your pick).
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| butterflybush, Buddleja davidii, Dublin, Ireland |
Far the best known butterflybush, however, is Buddleja davidii. It is native to most of China and was discovered for western science by Armand David (1826-1900) a Lazarist Catholic who was an early missionary to China. He was also a remarkable biologist (see Wikipedia biography: link). The species epithet davidii names the plant for him. The first was brought to Europe in the 1890s.
I'm going to call Buddleja davidii just butterflybush in this blog post. It is the only Buddleja that is widely cultivated. However, to distinguish it from other members of the genus you might say orange eye butterflybush.
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| butterflybush, Buddleja davidii |
The Chinese historically did not cultivate butterflybush, but it grew wild across many provinces, the flowers varying in color even in the wild. English plant collector and explorer E. H. "Chinese" Wilson (1876-1930) wrote of finding it northwestern Sichuan, "abundant by the stream side..a wonderful sight-- thousands of bushes, each one with masses of violet-purple flowers" (quoted by Lauener p. 33). Of course they brought it back to Europe and soon after it arrived in North America.
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| butterflybush, Buddleja davidii, Dublin, Ireland |
Somebody named it butterflybush, an evocative name. It is also called summer lilac. The Chinese name is daye zuiyucao which means "large leaf drunken fish plant." Several species of Buddleja in southeast Asia contain sapponins which stultify fish and are using in fishing. Those compounds are not found in Buddleja davidii but the Chinese name reflects that relationship. Surely buyers are more attracted to butterflybushes than drunken fish plants.
The flowers are clustered in large groups that naturally arch above the plant. They can be any color from white to reds and pinks to blues and purples. Buddleja davidii flowers have an orange center, whatever the overall flower color, although its intensity is very reduced in some cultivars. These flowers are attractive to butterflies...and to bees, flies and other nectar-feeding insects. They have a rich but not overpowering scent. In England, the plants were recorded to bring butterflies characteristic of the countryside into urban and suburban gardens.
Butterfly bush is a hardy shrub which tolerates poor soils and dry conditions. It can grow to six feet high, spreads about four feet but remains a clump. The oval leaves are a rich green in wild plants but cultivars offer other shades and variegation.
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| butterfly on butterflybush, Buddleja davidii, Cornwall |
For years, butterflybush was a highly praised garden plant. John Cretti in Rocky Mountain Gardener's Guide wrote in 2003, "Do you want to create a naturescape or wildlife friendly garden that attracts butterflies? Buddleia [sic.] should be at the top of the list for shrubs." (p. 210)
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| butterflybush, Buddleja davidii, Falmouth, Cornwall |
Currently, however, gardeners are recommending against planting butterflybush because it is invasive. In both Europe and North America it has naturalized widely. USDA Plants database shows it as growing as an exotic in 20 states (link) and the Invasive Plant Index finds it naturalized in several addditional states (link). It readily invades disturbed and wet areas and can out-compete native species. Breeders have responded to this by producing cultivars that are nearly sterile (less than 2% seed). But fully fertile plants are still easily purchased. Furthermore, nearly sterile is not the same as totally sterile; these plants can produce thousands of seedlings when planted in large numbers (see Cameron article link. )
Furthermore, in North Ameria, native butterflies do not use butterflybush as a host plant, so it feeds only adult butterflies but not their larvae. Other plants provide equally good nectar for adult butterflies but do support larvae, making another reason to plant something other than butterflybush.
The situation is not quite the same in England. It has naturalized in all parts of the country. However, a study in 1980 (Owen and Whiteway) found several native caterpillars feeding on it, that it attracted more adult butterflies than any other flower around, and, in summary "The shrub is in every sense a useful introduction, exploiting a previously unfilled niche, and its development of an associated fauna as well as the attractiveness of its flowers to nectar-feeding insects makes it a welcome addition to the British flora. " (quoting Owen and Whiteway's abstract). More recently, English wildlife organizations have pointed to butterflybush thickets in natural areas crowding rare species and growing on historic buildings speeding their deterioration. It is tricky to balance these views.
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| butterflybush, Buddleja davidii growing as a weed, Wales. |
England also has a different relation to butterflybush than the U.S. because in the 1940s, it quickly colonized bombed sites. Butterflybush spread green leaves and lavender flowers across the broken rubble produced by Nazi bombing. The English called it blitzweed. All over cities including London butterflybush was one of the plants, indeed the only garden introduction, that appeared within a year on the vast areas of shattered buildings. It grew to flowering in a year, produced numerous sweet-scented flowers, and attracted butterflies to blocks and blocks of devastation. Butterflybush was a cheery, hopeful sight.
Butterflybush thrives on calcium-rich soils, including all the mortar made available when buildings are destroyed. That is also why it is a threat to historic buildings.
Today it is widely naturalized in the United States and Europe. I think, given its aggressiveness and lack of support for larval insects in the United States, we are advised not to plant it but to perhaps admire it if seen on a roadside. "Look," you say, "Butterflybush. The English call it blitzweed because it grew in the ruins of Nazi-bombed cities."
For England, it is more complicated, probably requiring both admiration and control. Some plants are like that.
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| butterflybush looking beautiful along the coast Falmouth, Cornwall |
Comments and corrections welcome.
References
Cameron, L. 2022. Are butterfly bush cultivars labeled as "sterile" environmentally safer? Master Gardeners of Northern Virginia. link
Carlson, M. K. 2017. Blitzweed: the rise and fall of Buddleia davidii in England (1896-2008). Studies in the History of Gardens and Designed Landscapes. 37 (1): 87-96.
Cretti, J. 2003. Rocky Mountain Gardener's Guide. Cool Spring Prss. Nashville, Tennessee.
Hewitt, D. 2025.A Bombsite Flora: London’s Wartime Plants as Historical Facts. Architecture and Culture. 13 (1): 211-242. link
JSTOR Global Plants. Adam Buddle link
Lancaster, R. 2008. Plantsman's Paradise: Travels in China. Garden Art Press. Woodbridge, Suffolk, UK.
Lauener, L. A. 1996.The Introduction of Chinese Plants into Europe. SPB Academic Publishing. Amsterdam, Netherlands.
Owen, D. F. and W. R. Whiteway. 1980. Buddleia davidii in Britain: History and development of an associated fauna. Biological Conservation. 17 (2): 149-155.
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