Friday, August 17, 2012

The Butterfly Bush

Species name: Buddleja davidii

Common name: Butterfly bush

Location: Ontario

The butterfly bush is native to the Sichuan and Hubei provinces in China and coastal Japan. The B. davidii species is the most easily distinguished amongst all of the other species in the genus Buddleja: it has the orange centre of the flowers. Incredibly, there are over 600 species in the genus in total, and almost 100 different cultivars of this species alone! This shrub is described as having a "vigorous" growth habit, which would lead to the suggestion it has an invasive habit. Fortunately, due to the landscaping habits of most North Americans with this shrub growing in their gardens (hard pruning in either the spring or the fall), it has yet to become a major problem in most areas. Many popular cultivars are also less fertile than their non-modified ancestors, so that helps contribute to their lack of invasiveness in North America. That being said, it has been declared a noxious weed in Oregon and Washington. Further north it has difficulty surviving the harsh Canadian winters.

Given the common name, it shouldn't be a surprise what the major use of this plant is in landscaping: to attract butterflies. The plants also attract bees, hummingbirds, and moths. Amazingly enough, this is one group of plants that exists on every hospitable continent on Earth (the only non-hospitable being Antarctica, which is significantly too cold during the winter to be hospitable to any large plant). The morphological variation in this genus is relatively little (considering there are 600 species in the group), with most variation in flower colour and size. In the tropics some species attain a very large size due to the incredibly high productivity there, while some other species in sub-arctic and sub-antarctic areas are 10 cm or less off the ground.