Landscape architecture has come of age in recent years, and it’s a transformation James Corner, chair of Penn’s landscape architecture department, is only too happy to see. Yes, he says, practitioners in the field still design parks and gardens and open spaces, but increasingly they’re also being called on to reinvent blast furnace sites, former strip mines and other post-industrial remains that “nobody knows what to do with.”

These sites are often fraught with environmental issues, he says, “and yet have enormous potential, too.” Landscape architects are brought in both for their technical expertise and their ability to imagine new possibilities.

Corner, who also heads up the New York-based landscape architecture firm Field Operations, had to use all his visionary capabilities to imagine a new use for the Fresh Kills landfill site on Staten Island. The firm’s winning design, which is on display as part of the Museum of Modern Art's "Groundswell" exhibit through May 16, envisions the 2,200 acre site as a mixed-use landscape of grasslands, meadows, crop fields and wetlands.

“It’s not just scenic,” he says, “but an environment where life can re-root—fish, fowl, birds, crustacean life, new grasses.” Three times as big as Central Park and once the largest trash dump in the world, Fresh Kills is one of the few human constructions visible from outer space. In rethinking it, Corner had to deal with the “real constraints” of a landfill, such as soil and drainage problems, and the inevitable sinking of the landscape as methane gas escapes from the trash mountains.

He also wanted to redress its “negative, almost evil, past” and transform it into something that was ecologically positive. That meant not just restoring natural systems, but incorporating wind turbines and solar energy panels. In the level areas that were never filled with trash, his plans include restaurants, museums, art studios and nature facilities.

The design, which is titled “Lifescape,” includes a memorial to 9/11, since it was to Fresh Kills that workers brought the debris from the Twin Towers to be sorted. To commemorate that heroic effort Corner has designed an earthwork using the dimensions of the towers, “as if you laid them down on the ground.” Constructed on a slight incline, the earthworks will take 20 minutes or so for visitors to climb, and the final ascent will bring them level with lower Manhattan where the towers once stood. “I see this memorial not as an object to look at,” says Corner, “but an earthwork to traverse, to induce reflection.”

Corner’s vision for Fresh Kills will take years, perhaps decades, to fully materialize. One of the lessons he tries to pass on to his students at Penn is how to manage that long timeframe. “These projects are big, complicated and expensive,” he says, “but that doesn’t mean you have to wait 20 years before you get any results.”

The key, he says, is to think in terms of interim landscapes and early returns. “Maybe you just clean a site and throw down some meadow grass.” By making it open and accessible from the beginning, and making “the first stage just as cool as the final stage,” you avoid the long frustrating struggle to reach the finish line.

Corner and his colleagues at Penn also emphasize the importance of relating landscape architecture to the city. There’s been a shift, says Corner, from the 19th century, where landscape was the antithesis of the city, to the modern age where landscape is beginning to be seen in concert with modernism, frequently connecting into the city fabric rather than escaping from it.

It’s inappropriate, he says, to imagine recreating Versailles or Central Park. “The old models don’t pertain anymore.”