Profiles of Spontaneous Urban Plants

Although we tend to think of our cities as concrete jungles, our post-new urban environment is awash in plant life. This becomes especially apparent when you begin recognizing all the wild urban plants that have taken root along roadsides and chain-link fences, between cracks of pavement, and within vacant lots, rubble dumps and highway medians. Spontaneously propagating, these resilient plants find distinctive niches to thrive in and inhabit our most derelict landscapes. The environmental benefits of these “weeds” go widely unrecognized when, in fact, this often invisible urban ecology can offer a fresh perspective on how cities perform.

With that in mind, we staged an intervention to reveal the overlooked nature of urban weeds to the passerby: we painted rough, bright geometries onto the sidewalk along 3rd Street in Brooklyn, outlining spots where spontaneous urban plants have made a home. Using a typical street paint yellow, we drew circles around particularly important weeds that have emerged up through our sidewalks and tree pits – essentially taking a highlighter to the streetscape. Most people walk by unaware, only to stop for a brief second to consider why someone would be drawing attention to the weeds in the sidewalk. Sometimes, observant urban wayfarers linger long enough to glimpse the inconspicuous museum placard identifying the plants name, origin and characteristics.

“Profiles of Spontaneous Urban Plants” is a project conceived by Future Green Studio, our landscape urbanism firm based in Gowanus, Brooklyn. Our studio seeks to make urban interventions that reveal the nuances of our urban landscape in subtle, poetic ways that provide clues to the complex ecology of cities. Working out of a post-industrial neighborhood replete with sidewalk cracks, remnant gravel vestiges and dead end streets, overgrown urban weeds are ubiquitous in our daily experience.

In colloquial terms, of course, these plants are most commonly referred to as “weeds,” but are also known as “invasive,” “alien” and “exotic.” Culturally, the prevailing usage of “weeds” relegates these urban plants to an inferior botanical category because humans did not intentionally cultivate them at the particular site in which they have appeared. It is an understandable human reaction, as we have been taught, generally, that things which require little to no effort to grow, create, or maintain are worth less. But competing perceptions of certain plants reflect the need to think differently about the stigma we attach to these weeds. For example, Dandelion is perceived by suburban homeowners as an omnipresent lawn invader. But by children Dandelions are seen as a thing to play with, and by urban foragers they’re understood as food.

The term “invasive” denotes the biologically aggressive and exceptionally hardy characteristics of a plant, habitually denounced for taking over natural areas and stifling biodiversity. In non-urban conditions, these plants can at times be destructive on rural ecosystems. Monocultures of Tree of Heaven (Ailanthus altissima) or Common Reed (Phragmites australis) have been known to alter radically existing landscapes and wildlife habitats. With many invasive plants dispersing seeds multiple times throughout a season and with seed counts in the thousands per plant annually, the potential for a quick colonization of rural and suburban sites is a major concern.

The prolific nature of these plants, which makes them so dangerous in certain areas, also makes them incredibility successful in our urban ecology. As such, there is a movement to categorize these plants not as weeds but as spontaneous urban plants, and to recognize their importance as a sort of renegade green infrastructure, thriving in places no native plant would grow and providing substantive ecological benefits.

Our contemporary urban streetscapes and post-industrial vacant lots in no way mimic the Northeast deciduous forests of our past — once suitable growing grounds for native plants. Rather than trying to control our new urban ecology with the assumption that invasive species are degrading our environment, we should instead understand that without extensive maintenance of intentionally planted landscapes, most urban landscapes would quickly revert to being dominated by spontaneous vegetation. What’s remarkable about all spontaneous urban plants is the fact that they require no human assistance to assert and maintain themselves in extreme, often volatile urban conditions, while providing the same ecologically performative benefits of traditional landscape plants and street trees. Rather than seek to discard and eradicate them, we now have an opportunity to harness their benefits and tell their histories.

In the hard, difficult landscapes of contemporary cities, wild urban plants can provide real ecological benefits, and are the overlooked backbone of an emergent green infrastructure. For whether Daffodil or Dandelion, intentionally-planted or not, all plants contribute to lowering the urban heat island effect and can help address the carbon imbalance in our urban areas. Unlike many traditional landscape plants, spontaneous urban plants can also colonize disturbed bare ground, help with erosion control and slope stabilization, and be used as food and habitat for wildlife. In addition, Mugwort (Artemesia vulgaris) or Lambsquarters (Chenopodium album), for example, have phytoremediation properties and can be used strategically on brownfield sites to absorb pollutants from the soil. Spontaneous urban plants are also being rediscovered as part of our edible lexicon. Both Dandelion (Taraxacum officinale) and Common Purslane (Portulaca oleracea) are edible and highly sought after, finding their way onto plates at trendy restaurants.

In New York City, as with most major urban areas, stormwater retention is a particularly hot-button issue. Our storm sewer system here in New York City is completely overwhelmed, with raw sewage being released into our local waterways nearly half of the times it rains. Wild urban plants play an important role in slowing down the first flush of stormwater and reducing the cumulative impact of major storm events.

Another concept currently being explored that could utilize wild urban plants is the idea of brown roofs. Brown roofs are essentially paired down green roofs without the highly engineered soil and specialty plantings. With a much higher drainage profile, a brown roof is much simpler than a green roof, and can use the existing soil from the site – degraded or not. Although there are issues of fire safety that need to be addressed through seasonal maintenance, brown roofs include less upfront cost, minimal upkeep and a lighter weight load than green roofs. This strategy could radically transform our urban rooftops – providing all the benefits of a green roof at a fraction of the cost.

As an extension of the street intervention, we catalogued twenty wild urban plants we found growing on our street and in our garden. Individually set on a white background, each plant was photographed as a bare-rooted, singular specimen. Heavy shadows and sharp contrast play up the sense of plant specimen as object. Detail enlargements of the flowers or seeds are inset in each illustration and are accompanied by the plants’ place of origin, habitat preference, ecological function and cultural significance.

We applied traditional modes of botanical representation to these plants, which are not usually seen as “pretty” or “desirable,” and attempted to elevate them to the status of romantic illustrations of plants like lavender or thyme you might find hanging on someone’s kitchen wall. Using this whimsical approach, we intended to recontextualize these plants while at the same time revealing their cultural history, development and usage. For our work, Peter Del Tredici’s Wild Urban Plants of the Northeast: A Field Guide was an invaluable resource and has helped set the tone for recognizing this group of plants as an important part of our contemporary urban ecology.

As our cities grow in density, population and number, our urban landscapes must be both aesthetically pleasing and ecologically productive. By utilizing wild urban plants, we can design with a palette of greenery adapted to existing urban soils, widely available and attractive to pollinators and other wildlife. An informed combination of these factors can help create a pleasant urban meadow. As much as the upfront plant selection needs to play an important role, some designing will come through the process of subtraction. By removing diseased plants, those planted too close together or even the plants that are particularly unsightly or cause allergic reaction like Ragweed (Ambrosia artemisiifolia), designers can help to make the wild urban meadow tidy and kempt – and more appealing.

Additional research and reporting by Patra Jongjitirat.