The Easily Ignored Plants of Daily Life

Peter Del Tredici’s Wild Urban Plants of the Northeast serves not only as an absorbing field guide to spontaneous urban plants but also as a razor-sharp critique of how we value urban plants in general. In clear, jargon-free language, Del Tredici lays out his challenge to our ecological assumptions in the book’s introduction. He describes how we have a tendency to negatively judge plants that grow without human intention. Indeed, most of the plants described in this book are traditionally dismissed as weeds. Furthermore, we negatively judge plants based on their place of origin, labeling non-native species as “invasive.” Del Tredici argues that by automatically tagging these spontaneous urban plants as ecologically harmful, we ignore their potential benefits.

The entire concept of native and non-native becomes complicated when we consider the reality of urban conditions. Del Tredici challenges the notion that native plants can always be restored in urban landscapes, writing “(1) most urban land has been totally transformed from what it once was; (2) the climate conditions that the original flora was adapted to no longer exist; and (3) most urban habitats are strictly human creations with no natural analogs and no indigenous flora.” Cities represent entirely new conditions that native species are not necessarily adapted to. For this reason, native plants often require extensive human management to survive. Accordingly, Del Tredici dismisses the concept of urban ecological restoration as “really just gardening dressed up to look like ecology.” Instead, the plants that thrive in cities are already evolutionarily adapted for harsh conditions. Because they grow in cities without human input, they are, in a sense, the natural urban flora. These species can deliver significant benefits to urban ecosystems and should not be disregarded. For example, these species reduce the urban heat island effect, protect against erosion, stabilize stream banks, manage stormwater, create wildlife habitat, produce oxygen, and store carbon.

By challenging the way we value urban plans, the book forces us to reconsider how we design our urban landscapes. For this reason, the book is of particular relevance to landscape architects, though it is not specifically written for them. Discussions of sustainability frequently involve the use of native species, but how sustainable is a landscape that requires frequent maintenance? After all, plants that grow and flourish without human intervention are, by definition, sustainable.

Del Tredici touches on some landscape strategies that utilize spontaneous vegetation. These strategies involve the employment of selective editing – the targeted removal of certain undesirable species – to guide spontaneous plant growth to a desired result. He brings up the possibility of the spontaneously generated green roofs, high-performance urban meadows, and ecologically beneficial lawn alternatives. The design implications for spontaneous vegetation are vast and far beyond the scope of this book. For instance, spontaneous vegetation could be a tool for inexpensively transforming vacant urban areas into ecologically and socially beneficial spaces. Old industrial cities such as Detroit and Buffalo already grapple with the phenomenon of the “urban prairie.” Can these maligned spaces be turned into assets? Of course, any strategy utilizing spontaneous vegetation would need to fully address issues of safety, health and aesthetics. In New Orleans’s Lower Ninth Ward, a post-Katrina proliferation of spontaneous vegetation is generally seen as a threat to the neighborhood’s viability. Is there a way we can selectively edit this vegetation to benefit, instead of threaten, the neighborhood?

Del Tredici follows his eloquent 30-page introduction with the bulk of the book: a 300-page field guide to spontaneous urban plants. Each species gets a full page of text and a full page of images; by giving these plants visibility, he makes them impossible to ignore. Significantly, in addition to basic identification and habitat preference, each plant is described in terms of its positive ecological and cultural significance. These descriptions make the field guide an entertaining read and elevate it far beyond a simple tool for plant identification. Del Tredici deliberately omits any negative ecological qualities that these plants may have; the book aims to challenge our perceptions of these plants, not necessarily provide a balanced perspective.

By refusing to address any negative ecological consequences of these species, the book does lose some of its utility to landscape designers. While hinting at the potential of spontaneous urban species in landscape design, it does not work as a guide to their use. Similarly, while the book does bring up the strategy of selectively editing plant species, it does not describe how to kill them. While this information is useful and necessary, it is beyond the scope of the book. Written for a general audience, Wild Urban Plants of the Northeast is not intended as a guide to designing with spontaneous vegetation. Instead, it serves both as an eye-opening guide to plants often overlooked, and as a challenge to our notions of nature and the way we determine the value of plants.

In a culture where any alternative to the lawn can be controversial, we need to change the perception of wild greenery before we can design with it. Del Tredici strives “to teach people how to identify the plants that are growing in urban areas, and to counter the widespread perception that these plants are ecologically harmful or useless and should be eliminated.” In this aim, he resoundingly succeeds.

Read the book.

This guest post is by Benjamin Wellington, Student ASLA, master’s of landscape architecture candidate, Louisiana State University, and ASLA 2012 summer intern.

Image credit: Comstock Pub Assoc

5 thoughts on “The Easily Ignored Plants of Daily Life

  1. William Dempsey 06/13/2012 / 10:02 am

    Good for Del Tredici. The madcap rush to total native species requirements adapted by some municipalities and driven by misguided native ecology advocates has been a failure when applied to heavily disturbed areas. His “new natives” plus some more adaptive non natives do much better.+

  2. the author of this post 06/14/2012 / 2:34 pm

    If the suggestion being made here is that landscape design using aggressive adventitious species (i.e. weeds) would be “low-maintenance”, I submit that exactly the opposite is true. “Selective editing” would have high labor costs, and maintaining an “edited” condition over the long term would be more costly than ordinary maintenance of the typical, “horticultural” urban landscape, requiring more skilled labor. I don’t think such a landscape would survive client ire for long – assuming a client would accept it in the first place.

    Aggressive weeds, for the most part, evolved to take advantage of the disturbed conditions created by agriculture. In the continually-disturbed urban environment, they therefore have a competitive advantage against most horticultural plant materials we might use, whether they are “natives” or not. Any designed urban landscape must operate within certain constraints, and it is in the nature of urban weeds to continually violate any boundaries within which they are placed. Their tendency, in fact, is to create as extensive a monoculture of themselves as possible.

    This fact suggests to me the single biggest problem with trying to embrace urban weeds as part of conscious urban landscape design – allowing our planting choices to contribute to the degradation of urban biodiversity. Certainly some weeds provide some food to some species; but to which species, and at what cost? Even on so tiny a canvas as a human-designed urban landscape, we can plant for diversity in a much more effective and targeted way. (I agree with the above poster that there are a lot of knucklehead reasons why clients and stakeholders insist on “native plants only”; but supporting biodiversity is one of the best reasons to put native plants in the mix. Horticultural species can also help support biodiversity, with the application of some specific local knowledge.)

    It appears that this author may be more focused on aesthetic appreciation of “unintentional” landscapes and “accidental” plants than on the actual functions of urban landscapes. The aesthetics of “accidental” urban landscapes can and have been used as inspiration for designed landscapes. But as for the actual feral landscapes, wouldn’t they lose their aesthetic value and the sense of discovery they impart if an attempt is made to (partially) tame them and give them utility? Being stuck halfway between non-intentionality and intentionality doesn’t seem like a stable or sustainable landscape condition.

  3. B Davis 06/17/2012 / 11:17 am

    how do you know the edited versions would be more expensive? Are you really arguing that the maintenance for the “goats on Belmont” project or the way that the NPS manages Floyd Bennett Field is more expensive than something like the High Line? Do queen anne’s lace and goldenrod want to create monocultures of themselves? What about black locust? Are they native? The point is, those and a lot of other good plants are in the book, and they bring up good questions. The argument is more subtle and interesting than you are giving it credit for. I don’t think Del Tredici is calling for fields of chrysanthemum weed. Rather, he’s making the case that they have agency too, which must be contended with (via editing and even propagation, not just eradication).

    Also, to your point about “being stuck between intentionality…” I would argue that we now understand landscapes to be in exactly that position, and it is the development of techniques and tools (including concepts and ways of understanding) that can grapple with that reality that is where the most interesting work is occurring.

    In fact, I would say that being perched between “non-intentionality and intentionality” is fundamental to what a landscape is and always has been. That is why it’s interesting. The pine straw I want to spread around the hydrangea-and-magnolia ensemble I am planting (a banal example, I realize) is not dumb inert matter for me to completely manipulate as I please. Why imagine it that way?

  4. Xavier Faberman 06/29/2012 / 6:59 pm

    B Davis, to answer your questions: Yes, all living things, if not constrained, will create monocultures of themselves, from bacteria in a petri dish, to flu viruses in your body, to common weeds. Queen Anne’s lace is not native to the western hemisphere; with only 2 or 3 exceptions, goldenrods are native to the western hemisphere; and black locust is native mostly to the south central United States from where it extends into central Pennsylvania (it is not native to regions north and east of central Pennsylvania).

  5. jassodra 07/02/2012 / 9:35 am

    while watching the movie, I am Legend, i was very struck by the vegetation in the urban, undisturbed context. the movie scenes look quite inviting…that aside, while i have not read the book, based on this review, i think to focus on plants that grow ‘spontaneously’ is misleading. there is a whole ecosystem involved, particularly birds transmitting seeds into different areas via their droppings and the insects needed to pollinate these plants. there are natural ways to augment spontaneity and i think the a book such as this one would have done well to explore that context to get a greater appreciation for this idea of ‘natural selection.’ still, i look forward to reading this book.

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