Five years ago, landscape architect David Seiter wrote an essay for this publication explaining his interest in New York City’s weeds. Seiter’s project, “Profiles of Spontaneous Urban Plants,” was conceived as an effort to “to recognize their importance as a sort of renegade green infrastructure, thriving in places no native plant would grow and providing substantive ecological benefits.”
Earlier this year, Seiter, who is the design director and founding principal of Brooklyn’s Future Green Studio, published SUP: Weeds in NYC. Part guide, part coffee table book, SUP — which stands for “spontaneous urban plants” — is an enthralling survey of the plants we try to kill, when we notice them at all. (It has a companion website, too, that maps weeds in the city.)
This month, ecologist Timon McPhearson — who is the director of the Urban Ecology Lab at The New School, and wrote the foreword for SUP — sat down with Seiter to talk about the beauty and the performative value of the lowly weed, and how the propagation of spontaneous urban plants may shape the future city. New York has almost twice as much sidewalk space as park space. What if the former were as green as the latter? –H.G.
What is a weed? Are weeds good?
No, I don’t think all weeds are good. It’s not the intention of the website project or the book to be didactic and say all weeds are wonderful. There’s a general misconception that weeds means invasive. That is important to distinguish: “invasive plant” is a state designation. And New York State has a list of plants that are designated invasive and it’s often due to their impact on natural habitats, as well as their ability to rapidly replicate themselves and create large monocultures. “Weeds” is a different kind of term. It’s highly subjective.
Let’s take golden rod. It’s a native plant with ecological value in terms of wildlife habitat. It’s beautiful, it covers all the bases of what you might think would be a great weed. But it really depends on where it’s growing. If you find that plant growing in someone’s garden you might say, “What a beautiful flower.” If you find that same plant growing in the cracks of the pavement or along the base of a chain link fence, you might say, “Hey, what’s that weed growing there?” So it’s really about site specificity as well as actual plant qualities and type.
What kinds of goals do you think that these weedy plants can really serve? What are some places we can think about that have real potential benefit?
The sites we’re exploring are the sidewalks, the underutilized spaces on roofs or within vacant lots. In those territories, plants are growing where you might not even plant a plant. So I think there are all sorts of ecological services those plants might be able to offer depending on the plant type. We have found a lot of prostrate knotweed growing up between the cracks in the sidewalk that’s situated in an area that might be impacted by a combined sewer overflow. That plant will actually help to slow down the water that’s making its way to a drain and thereby reduce the impact on the sewer system.
That particular plant is constantly overlooked right? Nobody notices it or recognizes it. But through an aggregation of all those plants, it creates a larger system. And I think that can apply to storm water management. And it might be able to play into the discussion about urban wildlife and creating habitat corridors for different wildlife.
We have some idea that it’s going to get warmer and wetter. I’m curious, have you found any particular species that might be highly adaptive, and able to withstand some of the very harsh conditions that we have in the city?
Things like sumac, things like paulownia, that have been planted intentionally for landscape purposes, but are quick growing and resilient and offer a high degree of carbon sequestration. You get offered beautiful aesthetic value as well. So plants have the ability to function on multiple fronts.
We’re at the infancy of applying metrics to landscape and really looking at landscape for its performative qualities rather than its aesthetic qualities. We want to look plant by plant: How much does the ailanthus tree sequester carbon? How much water does it use? And then you can look at matrices of plants that go together, which, through their combination, might offer greater resiliency or offer a particular wildlife habit that they are unable to offer when standing alone.
I think making some distinctions about the site is really important as well. Central Park is different than the street. We need to understand each in isolation. Not very many people are really studying vacant lots, sidewalks, walls and chain link fences.
That’s something I’ve been extremely interested in, how we rethink the micro spaces across the city. If we take that lens, all of a sudden, there’s this potential for increasing the connectivity in the city and allowing species to move around. Both plant species that need corridors and movement, but also wildlife.
Absolutely. For me, weeds almost equals green infrastructure. Since 2008, we’ve dialed down larger sites like Brooklyn Bridge Park into more of a patchwork — into bioswales, into green roofs, into living walls, into vertical green strategies. But that’s just a kind of designer’s perspective. We really need to start having botanists and ecologists study those patch systems. One question I have: How small can a patch be and still be functional? And then what role do spontaneous urban plants play within those systems?
What size patches do we need and how close together? Some really basic questions. But on the whole it seems maybe not rocket science to suggest that if we did a better job with these smaller patches, and had more and more of them across the city, it would start to network the ecology. That’s bound to have benefits.
There’s things that the city should start to explore. There’s been a suggestion to situate green spaces around fire hydrants — a kind of generally unused city space. Our roads slightly crown — they push all the water to the curbs and the edges. Could we take that kind of transition zone between the street and the curb, call it a foot or 18 inches, and use that as a kind of infiltration zone or allow for plants to grow there?
Do you have some recommendations for how to work with weeds?
There’s a lot of different ways that we could think about designing with weeds.
One is from a straight conceptual vantage point. Look at the resiliency of the plant within its environment, and use that as a generative tool for landscape design. 41 Bond is a residential building on Bond St. between Lafayette St.and the Bowery, and it’s an all-bluestone facade with 24 integrated window boxes. We went to the quarry and looked at the striated nature of the bluestone, and the weeds that were growing out of the cracks of the stone face, and used that as a kind of generative tool with the architect to develop the concept.
Then there’s another idea of taking a vacant lot. We did this at another project called Nowadays, which is a beer garden out in Ridgewood, Queens, an 18,000-square-foot post-industrial site. Asphalt at one point; mostly vegetative at this point. We looked at designing by subtraction. What plants were particularly noxious, like ragweed for example, we’re going to eradicate all of that. A couple of the larger trees that were hugging onto the edges, like mulberry, like ailanthus, we chose to leave in situ. They offered shade to the site, and they offered a sense of scale. Roughly, some of them were upwards of 25 feet tall. And we didn’t see any particular reason to remove them.
Is there a particular recommendation you might have for how the Parks Department could think about this? Would it be different for an average renter or homeowner who wants to bring some nature and wildlife onto their roof or into their backyard?
From the design standpoint, a lot of the plants are not that available. A lot of urban weeds are successful because they have a taproot that digs down, it goes really deep into the soil and establishes a kind of greater sense of resiliency, right? Those plants are notoriously hard to cultivate. They don’t do well in small containers and pots and then they are difficult to sell.
So you can begin to start and use seeding strategies. So for example at Nowadays in addition to leaving certain plants in situ, we created the conditions to allow for certain seeds to germinate. And we did a lot of seed sowing. It’s also a strategy that’s being talked about by larger municipalities — doing seed-bombing of larger degraded landscapes. So using seeding as a strategy for regenerating both urban and non-urban areas is something that should be explored.
What kinds of things do you need to know to do your work? What do other designers need to know as well?
I’d like to know the metrics for each of the individual plant types, as much as that could be ascertained.
And by metrics you mean things like how much storm water can they absorb, how much CO2 can they absorb, what’s their real cooling potential in terms of evaporation. That kind of thing.
Part of this, it sounds like you’re suggesting, is bringing groups together to have a discussion about the real role of weeds in this city.
Across the board. Getting ecologists, getting city planners. Getting artists. Getting landscape architects to sit together and have a real substantive dialogue about what’s possible. One particular project that I’ve recently become aware of is through the New York Botanical Garden. Daniel Atha has been doing a survey of the kind of wild urban plants found in Central Park, and it’s going to be an amazing record of what Central Park had in 2016 in terms of its flora biodiversity.
That kind of study — along with our own website, which is a more designer science, but shows which plants across the globe people are finding and taking pictures of — is this kind of user-generated database of weeds. Where do those two lists start to interact and overlap and what are the connective tissues between different plant communities? And how does that inform our future?
It’s not just New York city. Cities all around the world are looking to green infrastructure to provide solutions to a number of environmental challenges that we have. What’s the next phase of this for you in the short term?
What’s been really interesting about getting the book out and having the website get a little bit more press is we’re starting to get hits from around the world. We’re starting to look at what plant communities are happening in Berlin, for example, or in Seoul, South Korea. And are there actual similarities between those plant communities, and what’s happening here in New York City or across the US? Maybe there’s urban flora which is pretty consistent between those different entities and something that actually might be even more of a driving force than the greater regional climate.
The views expressed here are those of the authors only and do not reflect the position of The Architectural League of New York.