Art of Landscaping

 

The Eda U. Gerstacker Grove on the University of Michigan’s North Campus is the modern anti-quad. The North Campus is cloistered and suburban, separated from the main Central Campus by a mile-plus and the Huron River. It’s home to the school’s College of Engineering, architecture school, performing arts school, and several residence halls. The campus is more than 50 years old, but until 2016 when the grove was completed, its central hub was an undistinguished plot of trees and walkways with little to no civic presence.

Unlike the more staid Central Campus (known as the Central Campus Diag because of its canted but axial tree-lined walkways), the grove is a landscape that is doing things while inviting passersby to do things as well. The landscape is filtering and retaining stormwater, boosting biodiversity, and putting on a light show at night and when it rains. Meanwhile, the students of the University of Michigan can try out the swings or kick off shoes for a game of sand volleyball. The Stoss Landscape Urbanism design for Gerstacker Grove links the 800-acre campus together, connecting natural systems to the built environment and creating an unmistakable campus center.

“With a lot of these moves, we’re trying to play off or against the traditional quad,” says Chris Reed, FASLA, the founder and director of Stoss. Quads are visions of collegiate life, where autumn breezes flutter golden-hued leaves onto broad lawns defined by stately and historic buildings. As spatial experiences, they can be laden with nostalgia potent enough to gather alumni from far and wide, and images of college quads grace many fund-raising emails. But they have limited utility on their own, Reed says; they’re mostly good for “image and circulation.”

But not Gerstacker Grove. With its varied topography and parametrically designed elements, the grove pushes at the edges of landscape architecture’s technological capacity, ecological performance, and expressive imagination. Who wouldn’t want a brand-new quad if it’s anything like the $6.9 million Gerstacker Grove?

Gerstacker Grove becomes more active and engaging as you move closer to the outer edges. Loosely surrounding a central paved plaza and carillon, five bioretention basins contain planted miniature forests that collect rainwater. To the east and to the west are moderately sized, wedge-shaped lawns between stands of trees and pedestrian paths. On the northwestern periphery are the grove’s most active uses, a sand volleyball pit and a set of swings.

The grove was funded in part by a gift from the Rollin M. Gerstacker Foundation (established by Eda in memory of her husband). The new landscape was shepherded by David Munson, then the dean of engineering of the school that surrounds the grove. Originally known as the North Campus Diag before the Stoss plan, the North Campus quad was a square crisscrossed by sidewalks, with a few trees and no benches. Though the North Campus is every bit as densely populated as the Central Campus, “There was nothing really to do there. The space was not activated,” says Munson, now the president of Rochester Institute of Technology. It was just a “pass-through,” and too big to be used only for circulation.

Considering the history of North Campus, it’s not really surprising that its central hub grew up without an identity of its own. From the beginning, North Campus was conceived as a decentralized, car-centric suburban experience.

Responding to the incoming wave of students from the G.I. Bill, the University of Michigan Board of Regents purchased the initial 267 acres northeast of the school’s main campus in 1947. The university was already hemmed in by the city of Ann Arbor for half a century, and it was deemed too expensive in terms of dollars and town-gown goodwill to buy up more land. So, the school looked to the farmland beyond and hired Eero Saarinen in 1951 to develop a master plan for the campus.

Saarinen’s proposal owed much to his suburban office park designs, especially the nearby GM Technical Center in Warren, Michigan, designed contemporaneously with the North Campus. Saarinen’s North Campus plan featured widely spaced, long, and rectilinear buildings, huddled around open fields and one hardscape plaza, with a domed amphitheater (similar to the Technical Center’s Auditorium) on the periphery. When this plan was new, “people used to go out and take Sunday drives for entertainment,” Munson says. With broad boulevards and ample space between buildings, the landscape was as spacious as a new sedan, but not scaled to the pedestrian.

The North Campus’s Cooley Memorial Laboratory was the first building completed, dedicated in 1953 to celebrate the engineering school’s centennial. Because of security concerns arising from a research partnership with the Department of Defense, administrators initially considered making the building accessible only via underground entrance. Ultimately, this plan wasn’t pursued, but an underground entrance was built and connected to a nearby nuclear reactor on campus.

According to Fred Mayer, who began at the university planning office when the North Campus was still new in 1966, Saarinen never got clear guidance on the size, shape, and position of buildings meant to fill in the North Campus, and the plan was ultimately shelved. “[Saarinen] established the basic pattern of land uses, the academic core to this day is where he said it should be, the research and support areas were all distributed according to his plan,” says Mayer, who became the university planner in 1968 and stayed till 2003, retiring to write two books on the planning and development of the Ann Arbor campus.

In one sense, acculturating engineering and science students toward landscapes that fit primarily between parking lots made sense—years of training on this campus could make the transition to Saarinen’s office parks for IBM or Bell Telephone seamless. Saarinen’s plan diffused the importance of a central gathering point and pushed the pedestrian experience that’s so beloved in college life to the margins. What the plan didn’t do was “develop a design concept for the [central space] itself,” Mayer says. What little planning there was, “was more related to the individual buildings than it was to an overall concept of the space.”

Sorting this out fell to Reed, who arrived with some revisionism in mind. “We wanted, in some ways, to critique [Saarinen’s plan],” he says.

There are small courtyards and landscapes elsewhere on North Campus, but they’re isolated islands, and the grove is really the landscape design that binds the architecture together. It connects to walkways at each corner, but with its parametrically designed spidering branches, it avoids drawing an axial X through the center of the square. The centerpiece of the grove is the hyper-postmodern Lurie Carillon designed by Charles Moore for his alma mater, but the surrounding buildings hover between unremarkable midcentury modernism and more subdued postmodernism.

In this design milieu, Gerstacker Grove stands out with a much sharper aesthetic presence across its four acres. It’s defined by a parametric precision that contrasts with messy edges of dense plantings. In addition to the 250 trees Stoss had planted (including bald cypress and serviceberry), five oblong bioretention gardens with a filter bed area of more than 10,000 square feet subdivide the space.

At the center is an asymmetrical plaza, surrounded by a series of spaces defined by topography. One of Stoss’s strongest moves was to alter the defining quality of the site. “It was pretty flat when [Saarinen] came there, but he got his bulldozers out and made sure it was completely flat,” Mayer says. In its place, Stoss designed berms that are 3.5 feet high, and the series of bioretention basins is only a bit deeper, but the contrast between the two creates a much more enveloping and spatially complex experience. Several features of the grove are meant to slow visitors down and push against the primary circulation role of many campus quads. If you venture on top of the berms, you’ll find a thicker fescue mix of grasses that require less mowing and maintenance and also provide a spongy texture that inhibits efficient movement and accentuates the sensory experience of the place. “It gets very shaggy, but it’s still soft,” Reed says.

The bioretention basins are planted with a dozen-plus types of water- and shade-loving ferns, including maidenhair and western sword fern. The dense ferns give the retention basins a misty, primeval feel. Each seems to be its own mole-scaled forest, self-contained and carefully composed. From bottom to top, there are gravel drainage streambeds to collect rainwater, a verdant fern understory, a surrounding bald cypress canopy, and high-density polyethylene canyon retaining walls holding it all in place.

The retention basins, which connect to a storage cistern under the sand volleyball court, help the university to meet its goal to retain 95 percent of stormwater on site. With its high clay content, the local soil doesn’t drain easily, and water is more likely to pool. “But we took advantage of that and said, ‘If we need that much capacity because it’s not going to drain quickly, let’s make a real feature out of that,’” says Reed. These planted basins help reduce peak stormwater runoff by up to 100 percent for a two-year, 24-hour storm event, and up to a third for a 100-year, 24-hour storm event. It also improves water quality by removing up to 80 percent of total suspended solids for a two-year, 24-hour storm event.

Like most of the hardscape elements on site, the berms and basins were parametrically modeled to meet the stormwater retention requirements. The concrete pavers and all the elements that separate the plazas and walkways from berms and basins were derived from digital models and installed as a prefabricated kit of parts: 19 types of oversized curb sections, 19 backless seat wall types, and five different metal seats made by Landscape Forms. Befitting an engineering school and the neighboring Taubman College of Architecture and Urban Planning, these elements are knit together in a sinuous transition from oversized curbs to metal benches: coiled steel ribs emerging out of the landscape like a snake. There are also Adirondack chairs to relax in that kept students lingering on a cool, fall day, and plenty of room to throw a football or Frisbee, which complements the sand volleyball pit and a set of swings that are popular all through the day and into the evening.

But it’s at night when Gerstacker Grove shows off the most. A lighting installation made of more than 100 transparent acrylic rods placed in the bioretention basins glows in shades of pink, blue, and purple—cool colors that stand out all year long. Brienne Musselman, who was a lighting designer at the lighting fabricator Illuminart for nine years and worked on this project, says the process of integrating these ethereal reeds of light into soggy outdoor gardens was both engrossing and painstaking. To set up a test rig to determine optimal light colors, Musselman disassembled headlamps chosen for their narrow band of light (similar in diameter to the rods themselves) and affixed colored filters snagged from a theatrical lighting company before replacing the test rod. She changed filters for each test, sometimes doubling or tripling them to get the exact shade she was looking for.

Prepping for these tests before meeting with Munson and Reed took hours, and she tried dozens of filters. She spent six hours in a pitch-black conference room with both of them. “It was extreme,” she says. “We went one by one, over and over…. ‘Do we like this particular hue? What do we think about this combination of hues?’ We tried amber and didn’t like it. It was actually really fun.”

The light fixtures are triggered by a simple irrigation collector (“It’s the same type of device that a farmer would use,” Musselman says) that registers moisture and turns the system on. From there, the lighting array can pull in real-time weather forecasts for the area, and this is what controls “fader” permutations, causing the lights to “shimmer.” (Musselman, like most lighting designers, doesn’t like the word “flicker” because of its connotation of disrepair.) She programmed the fade patterns in the field with two settings: a slower pace for light rain and more intense glimmers for torrential downpours. The dynamic fade cycles across each basin in a wave pattern, from one to the next.

Because it’s on at night and only puts on its full show when it rains, the installation slows visitors down when the urge to rush by is strongest. “Usually when it’s raining at night, you’re trying to run as quickly as possible,” Reed says. “We wanted to take that moment and invert it, [to] make it the most beautiful moment in some ways, but also use it as a way to connect people to what’s going on in the environment.”

With the grove’s maturing plantings, the lights are a subtle experience, particularly during the day when the transparent rods virtually disappear. Even at night, they’re just one element of many; little neon monoliths that glow but don’t illuminate. “That was one of the strengths of how Stoss designs [its] projects,” says Musselman, who now works at the Illuminating Engineering Society. “They’re not afraid of subtlety, and I think oftentimes lighting can be really in-your-face.”

If the Gerstacker Grove’s most distinctive features are subtle, its place and importance on campus are obvious. In his many decades as campus planner, Mayer came across a simple litmus test for how effective the design of a central quad is: “Say to a student, ‘I’ll meet you in an hour in the center of the campus.’ And if the student knows where to go, you’ve got a pretty strong image.”

Project Credits

Landscape Architect Stoss Landscape Urbanism, Boston. Client University of Michigan, Ann Arbor, Michigan. Lighting Illuminart, Troy, Michigan. Structural and Civil Engineering Mannik Smith, Detroit. Cost Consultant Fennessy Consulting Services, Stoughton, Massachusetts. Contractor J. S. Vig Construction, Plymouth, Michigan. Precast Concrete Bench Fabricator Wausau Tile, Wausau, Wisconsin. Metalwork Landscape Forms, Kalamazoo, Michigan.

Zach Mortice is a Chicago-based design journalist who focuses on architecture and landscape architecture.