Peter Del Tredici is a renowned botanist and horticulturist who worked at Harvard University, contributing extensively to the Arnold Arboretum in Boston and Harvard Forest. He is celebrated for his particular knowledge he developed of wild urban plants that thrive in the patchy, vacant spaces of East Coast cities—from Montreal to Detroit—and for highlighting their ability to cohabit “novel ecosystems” shaped by human activity.

Wild Urban Plants of the Northeast: A Field Guide was published by Cornell University Press in 2020, featuring a foreword by Steward T. A. Pickett from the Cary Institute of Ecosystem Studies. The second edition expands significantly on the original, covering 20% more species—268 in total. Since the first edition’s release, the accelerating impacts of climate change have made their presence an everyday reality. The book takes us on a journey around the corner, showcasing the (un)usual plant neighbours that populate urban environments. As an urban field guide, it highlights local weeds often encountered during an ordinary stroll. The attention given to the vulgare (commonplace) specimens is remarkable. Each plant description rivals those of cultivars, but here, “habitat preferences” are refreshingly unconventional: locations such as “rubble dumps,” “chain-link fences,” “rights of way,” compacted soils with high pH, and areas of full sun.

In the preface, Del Tredici states in an unaffected manner that the future belongs to plants that can keep pace with rapidly changing conditions, increased amounts of carbon dioxide, soil nitrogen and heat, regardless of how that makes us feel. Ruderals, as Del Tredici quotes Anne Whiston Spirn, are capable of “providing many of the same services that the cultivated plant communities do”, at no cost. Yet most city dwellers “are blinded to their beauty by a more domesticated aesthetics”. The book seeks to bridge this gap by bringing these “non-plants of non-places” into sharper focus for its readers.

What is groundbreaking is the change of perspective – Del Tredici’s argument is that these spontaneous plants are “de facto native urban flora” considering the novel conditions produced by humans. It is an argument against perceiving spontaneous vegetation including invasive, non-native plants and plants considered as weeds, to be less worthy. Labelling a plant “invasive” or “weed”, says Del Tredici, gives people the licence to blame it for ruining the environment and to get rid of it. What is native on one side of the planet can be invasive on the other, which inevitably traces the cultural exchange – and colonization. Weeds are defined by a context in which they grow unwanted and are symptoms of “environmental degradation” and not its cause. 

In this discussion, the focus is on urban environments shaped by human influence and aesthetic preferences, not on invasive species in natural or ecologically sensitive contexts. As Del Tredici points out in the book, while much of the criticism directed at non-native species is justified, their valuable contributions to urban ecosystems—such as the services they provide—are often overlooked. For example, in terms of ecosystemic services, those plants are capable of carbon sequestration and oxygen production, they enhance biodiversity, control erosion, produce organic matter, and reduce the temperature, among others. One of the most significant traits in service is phytoremediation, the detoxification of urban soils. By presented data, as much as a third of the of the terrestrial ecosystems are irrevocably altered by large-scale human activities in the wake of globalization, which makes novel ecosystems observed in cities a sneak peek into not-so-distant-future. Without consumptious maintenance, like watering, weeding and mowing, spontaneous vegetation will eventually dominate the altered land and we could take some benefit from it. 

Del Tredici’s gesture toward weeds parallels the act of a population census, recognizing the overlooked richness of urban life. Read between the lines, it confronts hygienic standards akin to predominant white culture with its narrow-minded views. It clearly states that the result seen now is a sum of unforeseen consequences of decisions and acts taken in past by individuals or officials. However, the book does not offer romantic views of the ruderal novel flora nor does it state its supremacy over the native. Instead, it provides more practical implications for future uses, giving numerous examples in specialist literature if we wish to dig “deep in the weeds”, to know how to create “freedom lawns” or intaglio plantings.

The title gives a deliberate charge by labelling the listed plants as “Wild”, opening the notion that we are dealing with plants that are perceived as uncontrolled, uncivilized, undomesticated and mostly unwanted in a seemingly controlled environment. Often linked with deviant activities that happen in neglected urban sites, wild plants receive negative connotations. The discourse on invasive and weedy plants helps us understand culture-instilled and subjective preconceptions. The book is an important step in the long line of efforts to recognise benefits and beauty of weeds and also a fun book to learn from.