Buddleia davidii (Butterfly Bush) was introduced to the United Kingdom in the late 19th century. Originally planted for its beauty, fragrance, and ability to attract butterflies, it is still coveted by many gardeners. However, Butterfly Bushes are now considered invasive and “problematic.” They were brought over for a specific purpose — their beauty and ability to attract butterflies — but once they jumped garden fences and began altering the landscape, they shifted from being coveted and exotic to being pests or invaders. They are equally reviled and beloved, now a part of the ecosystem, for better or worse.
Butterfly Bushes originated in central and western China. In this native habitat, they can be found in thickets along mountainous slopes. Their small, light seeds have a tendency to spread via wind. In the U.K., and Glasgow specifically, they often seek higher ground, growing on rooftops and walls. These persistent shrubs were one of the first things I noticed about the city upon arriving here — an unintentional architectural motif that wove itself into the fabric of urban grit and 19th century sandstone. A foreigner myself, I identified with them for their tenacity to make this place their new home. Like other immigrants, they enrich the city, injecting something new into the existing ecosystem, though sometimes their contributions are misunderstood or even spurned.
Butterfly Bushes have a habit of growing along railway lines, jumping from one town to another. Maps of their progress northward across the U.K. show a rapid, upwardly mobile spread that appears to defy gravity (much like their movement upward towards tenement rooftops). Try to uproot one, and you’ll discover that their woody stems are powerful anchors, tethering them to their new homes. In July, Glasgow explodes with vibrant purple blooms, and the air smells of honey. The silvery underbelly of their leaves catch the eye as they flutter in the same wind that carries their seeds to new territories. It’s difficult to imagine the city without them.