In February Sumana Roy, author of How I Became a Tree (2021), hosted an online symposium on the Plant Humanities at Ashoka University in India where she teaches. One of the speakers was Timur Hammond of Syracuse University, who presented on the trees of Istanbul, especially Ailanthus altissma, the tree of heaven, a weedy species native to Asia that has spread around the world. It’s familiar to most of us, which was one of Hammond’s points, and he described how in Istanbul it’s likely to be found in neglected areas like empty lots and untended graveyards. Hammond argued that it is a part of the urban landscape and urban culture, and therefore deserves more attention. Later, I contacted Hammond and he told me about a related book called The Botanical City edited by Matthew Gandy and Sandra Jasper (2020). It’s the subject of this last post in a series (1,2,3) on books that look broadly at cultural aspects of botany.
More and more attention is being given to urban botany as more land is taken over by cities and more of the world’s population is found in them. Many see this as a positive step toward managing climate change in that resources can be used more effectively in areas of high population density, allowing areas outside cities to be better managed as green spaces. The Botanical City focuses on the plant life present in cities, how it functions there both botanically and culturally. A number of articles are in the spirit of Hammond’s work: looking more closely at plants that many of us have long taken for granted or even disparaged. A quintessential example is the dandelion. Alexandra Toland’s essay, “Dandelions at Work,” focuses on how its flowers filter particulate matter from the air. Studies have shown that they capture most dust on the outer third of their circumference. In addition, the barbs of their achenes catch dust. Dandelion replicas made from microfibers also filtered the air, but dandelions do it much more beautifully and effortlessly. This species is hardly unique; anyone with an urban garden knows how different plants can look after a good rain. It’s not just that they may be standing up straighter, they also look brighter after a cleansing shower.
Mark Spencer, forensic botanist (Spencer, 2019) and former curator at the Natural History Museum, London, has an essay on the urban plants of London. He and several other contributors mention how cities tend to be hotter, drier, and windier than surrounding areas. He has been a student of London biota for years as evidenced by his observations on wall lettuce (Mycelis muralis). It is most abundant in areas north of the Thames River where there are many Georgian and Victorian brick buildings where lime mortar was used. Since this plant naturally grows in rocky soils with limestone, it does better here than in areas of newer construction with cement. This is a beautiful example of the diversity of microhabitats found in cities.
Seth Denizen’s essay on the flora of bombed areas also deals with London. He writes of a talk given right at the end of World War II by director of the Royal Botanic Gardens, Kew Edward Salisbury. He described the botanical diversity of the city’s bomb craters, a great example of the power of curiosity to make something positive out of devastation. Salisbury spoke of fireweed (Chamaenerion angustifolium) that “empurpled” these areas in the summer. He noted that this plant was apparently ubiquitous because of industrialization: “The bombing was a continuation of processes that had begun with industrialization that produced ash, fire, and bare soil” (p. 43). The plant was rare in London in the 18th century when William Curtis wrote his Flora Londinensis(1771). After the massive fire that engulfed the city in 1666, it wasn’t fireweed but London rocket (Sisymbrium irio) that grew in the rubble.
As these examples indicate, The Botanical City deals a great deal with urban ecology. It also explores the reality that urban wastelands with weedy areas are more likely found in economically impoverished sections. Examples are given from Houston, with its oil industry installations and in Lahore, India with abandoned railyards. Weeds can definitely have a cultural significance that we often ignore; they contribute to the unsightliness of neighborhoods that we would rather not see anyway.
In a section called “Botanizing the Asphalt” Livia Cahn has an essay on Japanese knotweed (Fallopia japonica, was Polygonum cuspidatum), its properties, and specifically how its flourishes in Brussels, Belgium. Like many weedy species, the knotweed grows fast on disturbed ground. The type found in Europe doesn’t produce fertile seeds, so it reproduces asexually. It creates rhizomatic root networks that spread down into the soil to three meters and out over seven meters. Even a small portion of root can produce a new plant in 10 days—impressive, if rather disturbing. Cahn describes how this knotweed can blanket disturbed land, and how goats have been brought in to keep it under control in a Brussels cemetery. They can’t kill it, but their aggressive feeding cuts it back so much that it grows more slowly, and the goats get fed and provide fertilization in the bargain. This is hardly nature at its most pristine, but it is nature, and for those who live in cities, it is a form that needs to be more appreciated and, shall I say, cultivated.
Gandy, M., & Jasper, S. (Eds.). (2020). The Botanical City. Berlin: Jovis.
Roy, S. (2021). How I Became a Tree. New Haven, CT: Yale University Press.
Spencer, M. (2019). Murder Most Florid: Inside the Mind of a Forensic Botanist. London: Quadrille.