Next time you find yourself on the west side of Chestnut Hill or Mt. Airy, look for how the streets follow the shape of the land and the leafy edges of Wissahickon Park.

In these communities, the feeling of the forest comes right up through the gardens and all the way up to the house.

That’s not by accident. Architects, planners, and preservationists inspired by the natural form of the valley developed a philosophy that treated the land as an essential part of their work. The result is more forest available not just to the houses that border it, but to anyone walking the streets above. They called it the “Wissahickon Style.”

Philadelphia architect Paul Cret saw it clearly in 1920. A modest city lot, he wrote, “could use the park’s woods as if they belonged to the house.”

Built from this place

That connection continues with the houses themselves, which were built of the same stone that glints along the trails of the park. Wissahickon schist, a silver grey rock flecked with mica, runs under most of Northwest Philadelphia. First quarried here in the early 1600s, it has been used ever since. By the late 1800s, Italian immigrant stonemasons were cutting and laying it. That combination of local material and imported skill lasted until the Depression shut it down, and it’s visible everywhere: in garden walls and steps, gateposts and foundations.

The gardens, too, were planted from local stock. In the early 1900s, Thomas Meehan ran the Germantown and Wissahickon Nurseries and William Warner Harper ran Andorra Nurseries. Between them, they supplied most of what grew in these yards — tall trees, a rich shrub layer, woodland wildflowers mixed with ferns, and compatible Asian groundcovers. Even the densely planted street trees seem to extend from the valley itself.

West Mt. Airy and West Chestnut Hill didn’t just border the park. They grew out of it.

A gradient of density

Walk through West Chestnut Hill from Germantown Avenue and you can see the density shift. The commercial strip on the ridge, developed primarily in the Colonial era, is a world of row and twin houses on small city lots. As the land begins to slope toward the gorge, the lots and houses get bigger. Squarish Victorian boxes on mostly flat yards give way, at the steepest part of the upper slope, to big rambling country houses built in the 1920s and early 1930s — perhaps what we think of as the most characteristic Wissahickon Style houses, with the park just beyond the property line. Without obvious visual boundaries, the properties seem to merge right into it.

This, too, is not an accident. The Woodward family, who developed much of this area, intentionally built properties that a variety of families could afford. Lot sizes ranged from 50-acre estates to one-eighth-acre properties. There were rowhouses, twins and triplets, houses arranged around a courtyard, and quadruplexes of four individual houses designed to look like one large mansion. The denser buildings read as a single rambling manor rather than multiple units, so the visual fabric held together.

The architects

Between the end of World War I and the onset of the Depression, the firms of Mellor, Meigs & Howe, Duhring, Okie & Ziegler, and Willing, Sims & Talbutt, along with individual practitioners like Robert Rodes McGoodwin and Edmund Gilchrist, were among the most talented residential architects working in the city.

Many of them had served in Europe during the war, where they encountered the Norman manor houses of France and the vernacular stone villages of the Cotswolds, buildings that seemed grown from the landscape over centuries. When they came home and turned their attention to Northwest Philadelphia, they saw that the local stone and wooded slopes of the valley offered a similar opportunity.

Mellor, Meigs & Howe, active from 1916 to 1928, were perhaps the best known. Reacting against the more formal Victorian and Edwardian houses of the previous generation, they built in a style that was loose, inventive, and responsive to the land. Their approach allowed for complex arrangements of varied spaces that worked with the demanding topography of Northwest Philadelphia instead of fighting it. Rooms aligned with light and views, and the buildings seemed rooted in the ground, not placed upon it.

They didn’t work alone. The Wissahickon Style was a collaboration among architects, craftsmen, and the land itself. Metalworker Samuel Yellin contributed ironwork. William Willet’s studio did stained glass. The Moravian and Enfield pottery companies made tile. Each element was specific to this place, made from local materials or shaped by local hands. Stone wall, stone step, stone house — all of it from the same ground.

The gardens of these properties create a rich series of outdoor rooms. Driveways aren’t just driveways. They’re transitions, designed to bring the forest right up to the front door. On larger lots, the lane winds through woodland before opening into a courtyard formed by the wings of the house and the garden walls. On smaller properties, it might be nothing more than a gap in a hedge or an arch in a stone wall. But the idea is the same: a brief passage before you arrive.

Once inside, the rear gardens face the park. The managed landscape dissolves gradually into the wild, with garden rooms giving way to lawn, lawn to plantings, and finally to the wooded edge beyond. The park becomes the largest outdoor room of all.

Roads, rails, and water

The thinking that shaped the houses shaped everything else. Henry Houston, who brought the railways from Center City to Northwest Philadelphia, made sure the tracks ran either under or over the built community, but not through it. The forested park flows through the neighborhoods unimpeded.

The roads work the same way. These neighborhoods have almost none of Philadelphia’s ubiquitous grid. The streets “woozle” along the contours of the land, following the shape of the tributary valleys. Leafy roads, lanes, and alleyways of all sizes wind through the neighborhoods, with trees planted so heavily that branches form arches overhead — the nave of a cathedral, with sidewalks as the green side aisles.

The water, too, moves the way it always has. Where streams and drainage channels needed to be managed, they were formalized into stone channels, pools, and spillways set into the hillside like features of an Italian garden. At the valley edge, streamlets meander through private lots, and drainage channels run as open rights-of-way between properties.

Keeping the water in the open matters. Exposed to sunlight and air, it cleanses itself naturally — something a buried pipe can never do. The permeable gutters along the streets slow the rain, letting it seep back into the water table rather than rush away into the creek.

The architects who built here between the wars understood that the point was never to show off the house. The point was to disappear into the beauty of the place.

Carol Franklin is a Chestnut Hill native, co-founder of the Landscape Architecture firm Andropogon Associates, and professor emerita of the Department of Landscape Architecture and Regional Planning at the University of Pennsylvania, where she studied under Ian McHarg. His landmark book, “Design With Nature”, changed the way a generation of planners and landscape architects understood their work.

George McNeely is an architectural historian, lecturer and writer of the occasional “Our Town” column in The Chestnut Hill Local. He co-edited “World Monuments: Fifty Irreplaceable Sites to Discover, Explore and Champion” (Rizzoli 2015).

This article draws on material from “Metropolitan Paradise, Philadelphia’s Wissahickon Valley” by Carol Franklin and David Contosta.