“Don’t throw it ‘away.’ There is no ‘away.’”
That waste-conscious message was scrawled on the back of a decades-old pickup in the Nebraska town where Martha Keen grew up. The doctor who drove it could have afforded a new one, but no: The truck had plenty of life left in it. Onward.
The phrase “there is no away” has become a tenet guiding Apiary Studio, a Philadelphia landscape firm founded in 2015 by Ms. Keen’s partner, Hans Hesselein, a landscape architect. Ms. Keen joined him soon after, and now the couple design and build outdoor urban spaces, many of them in residential settings, using as light an environmental touch as possible and creatively reusing what each site has to offer.
Yes, even slabs of old concrete, as well as what passes for soil in those urban settings. Really, it’s more like the stuff of a landfill, Mr. Hesselein said, or a postindustrial brownfield.
Standard practice in the trade would be to dig it all up, cart it away and bring in clean soil that would be easier on plants. But contributing to the waste stream doesn’t sit well with the Apiary team. Their design intention is to be regenerative, not to pass along — or compound — the problem.
“From an environmental standpoint, we wanted to leave the soils on site, not to make them some other community’s problem, wherever the landfill is that they would be shipped to,” said Mr. Hesselein, 42, the former director of the Gowanus Canal Conservancy, in Brooklyn. “And so we had to figure out what kinds of plants can handle the sharp drainage, the alkalinity, any pollution, the lack of organic matter.”
Except in vegetable beds and planters, where they use new, clean soil, they try to work with whatever is there.
The pair, who describe themselves as “concerned environmentalists,” said their resolve was reinforced early on, by watching how waste was handled at construction sites. “We saw building these landscapes as an opportunity to subvert that,” said Ms. Keen, 38, a graduate of the professional horticulture program at Longwood Gardens, in Pennsylvania.
Also, she said, “I just don’t necessarily want to be building landscapes that look like everything else.”
What they build instead — by de-paving key areas to open up planting beds and turning the excavated chunks into new walls or mosaic-like hardscapes underfoot — seems to work visually in Philadelphia, too.
“The aesthetic of this town is gritty, punk, improvised, layered with history,” Mr. Hesselein said. “Using recycled materials in the way that we do, particularly the rubble stuff, might not look appropriate anywhere. But in the urban environments where we’re working, they feel very at home aesthetically. That’s another thing that allows our work to be what it is.”
What it is, they are quick to point out, is not something they invented: They gratefully acknowledge pioneering regenerative landscape designers like Julie Bargmann, professor emerita at the University of Virginia School of Architecture and the founder of D.I.R.T. Studio (for Dump It Right There), as well as François Vadepied and Mathieu Gontier, of Wagon Landscaping, in Paris.
Apiary Studio received some acknowledgment of its own in March, claiming a best-in-show award at the Philadelphia Flower Show for “Right of Way,” an exhibit celebrating the beauty and habitat-restoring power of plants growing along the edges of highways — “an underappreciated green garland alongside the disturbance event of the roadways,” as Ms. Keen put it.
But when you’re working with such unconventional materials, there’s always the risk that the result may look too D.I.Y. How does what their website describes as “the adaptive reuse of urban decay” translate into a garden?
The Environmental Cost of Concrete
It’s not unusual for the Apiary team to arrive at a prospective client’s home for a consultation and find the whole place is paved — a common condition, they said, in urban Philadelphia or New York.
The first instinct may be to get rid of it all. But the modest budgets of the firm’s early jobs meant that was a no-go, even apart from Mr. Hesselein and Ms. Keen’s convictions about sustainability. Still, it’s hard to ignore the environmental impact of a material like concrete.
“Concrete has an outsized carbon footprint, as both a global industrial energy consumer and carbon dioxide emitter,” Ms. Keen said. “It also relies on dwindling natural resources to make, such as sand and gravel.”
In the face of so much waste, she said, Apiary’s strategy “is to intercept and build with it, and to limit our reliance on new concrete.”
That’s where another of the firm’s tenets — “addition by subtraction” — comes into play.
A demolition saw with a diamond-bladed circular wheel allows the designers to saw-cut “very clear, deliberate and geometric patterns in the existing paving,” Mr. Hesselein said, performing “surgical subtraction” to create beds with clean edges and “doing it in a very precise way that elevates that remaining concrete.”
The goal: to create something that looks more intentional — even elegant — and then to develop an equally thoughtful new life for the concrete slabs and other rubble that are lifted out and set aside, roughly sorted by size.
“When we start stockpiling these things, you start imagining stuff, and you let it incubate in your mind while you’re working on other tasks — while you’re completing the demolition, while you’re prepping the paving base,” Mr. Hesselein said. “So you’re inevitably, invariably thinking about these things and imagining these scenarios of different patterns.”
A series of mock-ups helps them, and their clients, find their way to a design that turns debris piles into “a mosaic of mixed pavers,” he said.
Other artifacts the site may cough up — old bricks, cobblestones and rocks, sometimes accompanied by irresistible castoffs retrieved from the transfer station — become part of the improvised mosaics. Think of it as terrazzo with a twist.
“When you pave with rubble concrete, these broken-up pieces of sidewalk, it looks a bit like terrazzo,” Ms. Keen said. “Rubble terrazzo, a funny mimicry.”
Thanks to clients who are open to exploration, the couple’s designs have become increasingly refined. Among the tricks they have learned: making sure that several pieces of rubble — up to 25 percent of the design — are as large as possible, to create contrast with all the smaller ones.
“Big, big, big pieces. Big like couch-cushion huge, or the entire slab of a sidewalk,” Ms. Keen said.
“We call them shiners,” she added, because they catch the eye. Trash turned to treasure.
An Urban Plant Palette Emerges
With paths in place and beds defined and ready for plants, the question is: Which ones?
To figure that out, the designers visualize places in nature with similar conditions, the “analogous ecosystems and plants that can handle such soil — with soil in quotes,” Mr. Hesselein said, referring to areas of chalky dirt or outcroppings of shale, or where industry has left behind an altered landscape, like slag heaps.
These are not gardens that welcome ericaceous plants — acid-lovers like azaleas and other Rhododendron, or blueberries. Instead, Ms. Keen said, she and Mr. Hesselein use “plants that have bold texture and take up space.”
One real workhorse is sea kale (Crambe maritima), a giant perennial Brassica with silvery-blue leaves, topped with sprays of small white flowers. “It seems to be happy, and to get enormous in almost any urban condition we put it in,” Ms. Keen said. “Like three-foot-by-three-foot rhubarb size.”
Another perennial they turn to is cardoon (Cynara cardunculus), a cousin of the artichoke. “I have a real penchant for glaucous plant material,” she said. “Blue-gray tones seems to marry well with the concrete and rubble material.”
Herbs like common sage, rue, rosemary, lavender and santolina fit the profile, too, happily thriving without irrigation or nutrient-rich soil. Other tough Mediterranean favorites: donkey tail spurge (Euphorbia myrsinites), wood spurge (Euphorbia amygdaloides var. robbiae) and bronze fennel.
A striking color contrast that also finds its way into nearly every design is native butterfly milkweed (Asclepias tuberosa).
These are unexpected, experimental landscapes, the couple concede, but they are determined to continue experimenting — for the creative challenge they thrive on, to pursue their environmental goals and to provoke new thinking about our built landscapes.
“Only one person has ever come to us and said, ‘I want this recycled landscape aesthetic in my garden,’” Mr. Hesselein said. “Only one client ever.”
But they like to imagine a day when people will have seen enough examples in the world to start asking for such sustainable thinking in garden design.
“I believe that the people who hire us are looking to break from convention,” Ms. Keen said. “And, like us, understand that even garden making is not absolved of having a carbon footprint. And that, like we do, they love how recycled landscapes look.”
Margaret Roach is the creator of the website and podcast A Way to Garden, and a book of the same name.
If you have a gardening question, email it to Margaret Roach at gardenqanda@nytimes.com, and she may address it in a future column.