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Ruderal Landcapes + Urban Nature Management

The notion of the ruderal helps shine light on urban nature as intricately entwined in human social, political, and economic relations. It refers to nature that takes hold as a result of human-induced activity--nature unplanned and unruly but not wild. Considering this intrinsically fluid nature, management of ruderal ecologies takes many forms as it collates a variety of perceptions and discourses contingent on the types of stakeholders and priorities involved in each situation.

As part of the urban, ruderal spaces are seen as opportunities to generate benefits for the community other than the cultural and scientific values they embody as part of an “unintentional landscape” (Gandy, 2016). Vacant parcels, the theater of the ruderal in the city, are often portrayed as “urban voids” or “negative spaces” (Kim et al, 2018). Both residents and city officials confronting vacancy therefore want to turn this absence into a presence capable of contributing to the general welfare. Expectations for these spaces may differ between residents, organizations, and authorities according to their own interests and assumptions: should vacant land be reserve for future real development or be repurposed for a public park? A tax-paying urban farm or an informal space for subsistence gardening? Inexpensive low-touch maintenance or targeted, ecological management?

Despite these different views of land use, a consensus emerges around the “mutual benefits” of transforming vacant parcels, and is frequently deployed to present projects and policies as profitable to all parties involved. This consensus narrative is rooted in the assumption that putting the vacant land to “good use” is necessary to prevent blight, which is itself “very discouraging for residents and conveys negative images about their community” and is associated to “marginal and illegal activities and crime” (Paddeu 2017). City governments and local actors have therefore developed policies to manage, control, reduce or guide the effects of urban vegetation on vacant land in the service of interests considered beneficial for the community as a whole.

In the cities researched in the Rust Archipelago project, numerous public voices have been raised to take advantage of “vacant, abandoned of unproductive land parcels” for the benefit of the community (Draus et al., 2020). Through examples in St Louis, Detroit and Philadelphia, this memo will look at the issues, paradoxes, conflicts, and incompatibilities that can emerge from different visions of the city when it comes to characterizing these spaces and defining their use. It will however also the highlight the potential of ruderal and vacant spaces as places that can tie together different sets of values around common emancipating projects based on knowledge.

The utilitarian imperative and the limits of mutual benefits

Urban ruderal ecologies, as the result of man-made disturbance on the environment, are usually considered in the context of vacancy. Vacant parcels however are not a homogenous category, and vacancy doesn’t equate an absence of management. The term can encompass a variety of situations with different material, spatial, and physical forms. The presence of vacant land in a city triggers a series of government-led or community-based (re)actions that depend on the type of space, its location, the potential benefit it can generate and the actors that can be mobilized around it.

In their study of vacancy in Roanoke, Virginia, Gunwoo Kim et al. categorized five types of urban vacant land: post-industrial, derelict, unattended with vegetation, natural, and transportation-related (Kim et al., 2018). Each of these types can be host to ruderal vegetation, but they each embed distinct social, legal, economic and aesthetic relations that guide expectations associated to them in terms of land use or productivity. Kim and colleagues’ study focuses on the opportunities to “develop [the] ecological and social value” of vacant land, as either support for green infrastructures or wildlife refuges.

Gunwoo Kim and colleagues categorized five types of urban vacant land: post-industrial, derelict, unattended with vegetation, natural, and transportation-related. Each can host ruderal vegetation, but they embed distinct social, legal, economic and aesthetic relations.

Even if vacant parcels “are often seen as suspended in limbo, unworthy of any planning or consideration until such time as a new use becomes available,” experience has shown that they represent “a common and a substantial proportion of the urban landscape that is available for strategic reuse in urban development policy.” Vacant parcels and their ruderal ecologies are either a reserve for future land development, or a dormant resource to be activated, developed or made productive, but not as worthy in relation to their actual, current values. They are only a potential that can be tapped into through material or discursive transformation (by changing the aspect of vacant spaces or the way we look at them).

A form of productive use for vacant lots and ruderal spaces that has been abundantly covered by scholars is urban agriculture, which represents “a tool for education, economic development, food security, leisure activities, social interactions, health, and urban development, as well as for environmental enhancement” (Paddeu 2017). While it is often identified as a spontaneous initiative by residents in response to their direct needs, urban agriculture has in most places been co-opted by local authorities who want to maximize the social and economic benefits of this form of land use. Lawson and Miller relate how community-led urban agriculture initiatives emerging as early as the 1970’s in cities experiencing abandonment have been progressively reclaimed by city officials under the justification that residents cannot sustain urban agriculture projects in the long term on their own (Lawson and Miller 2013).

In addition to the reach of policy into residents’ backyards, it is also the “mutual benefits narrative” used by local authorities for urban gardening that has to be analyzed and nuanced. Flaminia Paddeu for instance explains how the city of Detroit has intended to use urban gardening and farming as part of a "smart decline" planning strategy, but the implementation of this policy didn’t fully take into account the multifaceted dimensions of long-term abandonment. Many crucial questions remain unanswered, including: the racial and social equity of urban food distribution, the pertinent scale of urban agriculture in relation to the needs and practices of residents and urban farmers, the deperate need for soil amendment, and protection against risks of displacement (Paddeu 2017). The promise of mutual benefits through putting vacant land to ”good” use is therefore one that is not easily fulfilled.

Vacant lot, abandoned building and ruderal vegetation in Detroit (Google Earth caption, May 2019)

The Clean and the Green: Competing Views of Ruderal Management

Grass cutting on vacant parcels is a complex issue that mobilizes many factors. Concerns as varied as health, safety, aesthetic perceptions, ecological services, biodiversity and public finances are weighted and debated between city government, residents and advocacy groups. While arguments are formulated in favor of leaving ruderal vegetation and minimizing maintenance, legitimate counterarguments are rooted in the negative experience of residents and local authorities. Like many cities burdened with large amounts of vacant land, Detroit has implemented a calendar of regular cutting in order to “keep the grass at an acceptable level and promote community safety to improve the neighborhoods” (City of Detroit 2021). Block clubs, homeowners and community organizations can choose to opt out of the city mowing if they maintain the land themselves. However, academics and environmental organization have been putting forward arguments to reduce grass cutting to increase biodiversity, improve community health and climate resilience.

A University of Michigan research team conducted a study on grass mowing found that while ragweed – a source of allergenic pollen – was mostly found in vacant lots, unmowed vacant parcels in Detroit produced less ragweed that the ones mowed annually or biannually. They recommended one of two management practices to reduce the effects of ragweed: either mow parcels frequently (monthly) to limit the sprout of ragweed, or not mow at all to let it be outcompeted by other species. The latter proposal was the one mostly used by the press to report on the findings (“How Detroit's Vacant Lots Could Help Allergy Sufferers”, “No Mow: Controlling Ragweed Pollen in Detroit”, “Will Allowing Vacant Lots to Grow Wild Ease the Pain of Allergy Sufferers in Detroit?”), showing the possibility of a space for a discursive and cognitive shift regarding “unmaintained” spaces: from undesirable sight to contribution to community health (although that space may exist only for a very specialized audience which is not necessarily the one experiencing the adverse effects of vacancy).

Vacant lot in Detroit: vacant lots are both a contributor and a solution to pollen allergies. (Image credit: Daniel Katz)

In 2021, the Northern Institute of Applied Climate Science -- an organization working with the US Department of Agriculture with an aim to foster collaboration between scientific researchers, landowners and natural resources managers on issues relating to climate change – organized a workshop on climate change adaptation in the Detroit region’s urban forest. Urban forestry is seen as a means to attenuate the effects of climate change, as a rich biodiversity can recover better from disturbance caused by flood, fire or drought. The urban forest, which can include vacant land, is in this context a green infrastructure necessary to support the city’s transition into an uncertain future. The workshop was organized with other local or national environmental organizations and the City of Detroit. Participants designed a series of measures which included a section on mowing. Measures encouraged adapting the City’s mowing program to allow for other forms of land care, introducing flexibility, diversifying management tools and limit harm to ecosystems. They also proposed to rename to mowing program, which can be interpreted as an attempt to contribute to this discursive and cognitive shift regarding spontaneous vegetation.

The Detroit Climate Action Plan, a collaborative work led by the Detroiters Working for Environmental Justice and characterized as “bottom-up climate resilience plan”, was published in 2017. Though prefaced by the Mayor of Detroit, the Plan is not a city-led policy, and local governments are not bound by the plan’s objectives. Its section on “Parks, Public Spaces and Water Infrastructure”, which aims to “increase the resilience of ecosystems services”, mentions the creation of no-mow zones as “an opportunity to expand natural habitat areas”. The section does not talk of vacant land but of “open space” instead (a vocabulary also used by the policy think tank Detroit Future City in their plan “Achieving an Integrated Open Space Network in Detroit”, which advocates, among other measures, for the development or urban prairies and meadows).

The indicators for success used for this measure are the expansion of “no-mow zone/low maintenance using aesthetically pleasing techniques in areas where public use is low” and the installation of “educational signage explaining no-mow zones and other alternative uses”. The phrasing of these indicators show that in order for these open spaces to act as green infrastructures to improve the city’s resilience, they must comply with the public’s expectations in terms of aesthetics (the fact that the plan is the product of a community-based efforts is testament to the importance that residents attach to aesthetics and order in green spaces). Unlike the Climate Action Action, the Sustainability Action Agenda – Detroit’s own plan, published in 2019 -- does not integrate vacant land vegetation, meadows or prairies into its strategy to address environmental challenges. The city is however working on a new Climate Strategy that will replace the previous Agenda.

All of these arguments based on health, resilience and climate adaptation concerns emerging from different organizations haven’t contributed to changing the city’s grass maintenance policy, which still consisted in late 2021 in a four to five times a year cutting program based on a strict schedule. Demands for cutting are however equally understandable as they are based on day-to-day experiences that contribute to the deterioration of the residents’ living environment beyond preconceived notions of what urban nature should look like. For instance, tall grass makes it easier for people to dump thrash, and wild dogs are not noticeable and pose a threat to children (Fox 2 Detroit 2015).

Volunteer resident mowing a vacant parcel in their neighborhood (Image credit: Fox 2 Detroit

Another example of this paradox between the recognition of the ecological and social services of vacant land and public demands comes from Flaminia Paddeu’s study of Detroit urban agriculture program. The City of Detroit Urban Agriculture Ordinance states that lots have to be “maintained in an orderly and neat conditions”. “High grass, weeds or debris” are not accepted either, and animal husbandry (including small species such as chicken, rabbits and bees) has been prohibited for fear of rodents. These restrictions were a response to the community’s demands, for whom “urban agriculture is an impaired form of urbanity, and a visible symptom of decade-long urban decline residents would prefer to deny” (Paddeu 2017).

In addition to the city of St. Louis’s mowing program, the non-profit organization “Brightside St. Louis”, dedicated to both “cleaning” and “greening” St. Louis and making it a “cleaner, brighter and better place to live”, developed a series of programs to foster citizen action to improve their living environment.

Beyond aesthetic and psychological arguments for cleaning, Brightside’s efforts also aim at reducing very concrete health threats such as the transmission of disease from mosquitoes, through the elimination of sources of standing water (such as flowerpots and trays, tire swings or abandoned tires, birdbaths, pet dishes and toys). While the city of St. Louis is also conducting actions to prevent the propagation of mosquitoes, some of their measures depart from those recommended by Brightside. The City’s Department of Health conducts precautionary fogging on a block basis, which residents can opt out if they choose. Brightside, on the other hand, considers this practice unsafe and ineffective, as it only kills adult mosquitoes and not eggs and larvae, in addition to killing all insects in contact with the fog, including pollinators and other insects who prey on mosquitoes. Here again, actions by different stakeholders towards a shared objective are implemented differently. Potential causes can be looked at organizational constraints in the city services, or a belief by residents, employees or city officials that fogging is the most efficient solution considering the scale of the problem.

These examples help us to see that the effort to bring the positions of environmental organizations, city officials, and residents closer together requires a shared understanding of the problem at hand, not rooted in preconceived discourses but established as an empirical construction of the knowledge of a community’s immediate natural environment.

Cleaning operation organized by Brightside St. Louis (Image credit: Brightside St. Louis)

Landscape Literacy in West Philadelphia as a Vision-Building Process

An example of a project to build a common understanding of a community’s resources is the West Philadelphia Landscape Plan (WPLP), an initiative led by landscape architect Anne Whiston Spirn with the University of Pennsylvania that started in the late 80’s. The project focuses on the Mill Creek neighborhood of West Philadelphia, an area with a large proportion of vacant land and buildings and a strongly segregated population. The historical creek that used to run across the area was buried in a concrete channel in the late nineteenth century to protect residents from sewage and water-borne diseases. As the city expanded on the surface, more and more buildings were connected to the sewer which eventually could not contain anymore the combination of sewage and storm waters in the event of rainstorms. The situation produced sewer overflows, causing still more water pollution.

Throughout the twentieth century, the neighborhood saw numerous cases of buildings and parts of the sewer caving in, since, despite the burial of the creek, the area still functioned as a floodplain. The population flight that started from the 1950’s onward resulted in the demolition of many buildings, some of which were located right above the creek and should never have been built in the first place. Spirn and her team therefore saw the situation as an opportunity to revive among residents the lost memory of the creek through “landscape literacy,” in order not to repeat the mistakes of the past and to empower residents through the knowledge of the natural cycles of their living area.

Spirn’s efforts were also a reaction to the absence of consideration from the City Planning Commission for the health and safety of residents in relation to the natural workings of the creek: “I began to understand this resistance [from the City Planning Commission] as a form of illiteracy—an inability on the part of public officials, developers, and even Mill Creek residents themselves to read the landscape” (Spirn 2019). She explains that the ability to read landscape “is also to anticipate the possible, to envision, choose, and shape the future: to see, for example, the connections between buried, sewered stream, vacant land, and polluted river, and to imagine rebuilding a community while purifying its water.” Through landscape literacy, what was previously regarded as vacant, unproductive parcels bearing the historical weight of the neighborhood’s abandonment became an integral part of the watershed’s natural operation, while the injustices of the past were made visible and widely known. The program especially targeted public schools, where students used their newfound knowledge to question city officials on issues of spatial segregation, planning, urban policy, health and environmental risks.

Through landscape literacy, what were previously regarded as vacant, unproductive parcels bearing the historical weight of the neighborhood’s abandonment became an integral part of the watershed’s natural operation, while the injustices of the past were made visible and widely known.

After gaining national public attention in the late 1990s, the program lost momentum following the departure of key protagonists amidst an administrative re-organization of school districts. However, the project is worth considering for its efforts to depart from taken-for-granted narratives of urban management and to rebuild instead a shared knowledge of the place in all of its complexity. The ambitious plan passed by the City in 2009 to reduce combined sewers overflows through green infrastructure can be credited in large part to the WPLP and the attention it received.

Vacant land on the buried Mill Creek floodplain: an important ecological role going unnoticed (Still from “The Buried River”, Anne Whiston Spirn/WPLP

Building from the example of Philadelphia, a form of shared “ruderal literacy” between residents and officials, which looks at urban nature under all of its dimensions, functions and potentialities – aesthetic, cultural, scientific, discursive, social, sanitary, psychological, recreative, ecological, technical – can be a way to start an informed conversation in other cities about uses, opportunities and benefits that are truly chosen, desirable and sustainable.


Brightside St. Louis.

City of St. Louis, Health Department, Information about mosquitoes and preventing West Nile.

Climate Change Response Framework, City of Detroit Parks: Infusing Resilience into Capital Improvement Planning and Maintenance for Parks Systems.

Detroit Future City, Achieving an Integrated Open Space Network in Detroit, 2016.

Fox 2 Detroit, 2015. Volunteers mowing vacant lots ask for help, August 13, 2015.

Gandy, Matthew. 2016. Unintentional landscapes. Landscape Research 41, no. 4:433-440.

Hickman, Matt. 2021. Review of Will Allowing Vacant Lots to Grow Wild Ease the Pain of Allergy Sufferers in Detroit? Treehugger, February 23, 2021.

Katz, Daniel S. W., and Stuart A. Batterman. 2019. Allergenic pollen production across a large city for common ragweed (Ambrosia artemisiifolia). Landscape and Urban Planning 190, 103615.

Katz, Daniel S. W., Benjamin T. Connor Barrie, and Tiffany S. Carey. 2014. Urban ragweed populations in vacant lots: An ecological perspective on management. Urban Forestry & Urban Greening 13, no. 4:756-760.

Kim, Gunwoo, Patrick A. Miller, and David J. Nowak. 2018. Urban vacant land typology: A tool for managing urban vacant land. Sustainable cities and society 36, 144-156.

Lawson, Laura, and Abbilyn Miller. 2012. Community Gardens and Urban Agriculture as Antithesis to Abandonment: Exploring a Citizenship-Land Model. In The City after Abandonment, edited by Margaret Dewar and June Manning Thomas, 17–40. Philadelphia: University of Pennsylvania Press.

Metcalfe, John. 2014. How Detroit’s Vacant Lots Could Help Allergy Sufferers. Bloomberg/CityLab, June 17, 2014.

Millington, Nate. 2013. Post-Industrial Imaginaries: Nature, Representation and Ruin in Detroit, Michigan. International Journal of Urban and Regional Research 37, no. 1:279-296.

Paddeu, Flaminia. 2017. Legalising urban agriculture in Detroit: a contested way of planning for decline. Town Planning Review 88, no. 1:109-129.

Spirn, Anne Whiston. 2019. Landscape Literacy and Design for Ecological Democracy: The Nature of Mill Creek, West Philadelphia. In Grounding Urban Natures: Histories and Futures of Urban Ecologies. Edited by Henrik Ernstson et al., 109–136. Cambridge: MIT Press.

West Philadelphia Landscape Project.


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