Pergolas enjoyed renewed popularity in the first quarter of the 20th century. In fact, judging from photos in the period’s home journals, some architects appeared to have pergola-mania. Elephantine columns (in wood, stone, or brick) supported elaborate beam-and-rafter assemblies that carried masses of vining and flowering plants. Gustav Stickley, the furniture-maker and style guru, insisted in his magazine The Craftsman that the pergola was the best way to unify the house and its landscape, an ideal of the Arts & Crafts movement.
Most of those old wooden pergolas are long gone, but the recent gardening revival has rekindled interest in garden structures. Whether as a promenade, a covered terrace, or a freestanding garden feature, a pergola is a bold statement worth making, with practical advantages as a sunscreen and as a support for plants. A pergola may spring from the building or stand on its own. Shading the carriage doors, a narrow pergola-sunscreen is a softening feature on many new garages. There’s a pergola for every style, from formal Italian to Adirondack, California, and Prairie School.
Precedent suggests, though, that the pergola does not have to match the style of the house. The eclecticism of 20th-century domestic architecture was reflected in pergola designs. Beaux Arts classicism vied with rustic styles (even pole pergolas made of woodlot saplings). Neo-Georgian colonnades were affixed to rambling Shingle Style and vernacular American Foursquare homes; elsewhere, rustic “twig” pergolas sat behind symmetrical Colonial Revivals. Many pergolas were non-historical, neither classical nor rustic: Look for round supports that have no capitals or plinths (bases). Square support piers, especially in stone or brick, were also popular.
In the Midwest, many of these exterior structures show the influence of the Prairie School, with robust masonry. Built of redwood, a pergola is at home with the adobe houses of the Southwest. In the Northeast, pergolas are suitably quaint when supported by stone or brick; alternately, they carry delicate latticework and are painted colonial white. A Japanese influence predominated on the West Coast, where pergolas featured fancy-cut rafter tails, brackets, and framing with graceful Asian motifs. Pergolas could be bungalow-basic or rendered in high style in the manner of Pasadena architect–woodworkers Greene & Greene.
A Short History
Pompeii had pergolas, and so did Rome; to this day, the Western pergola tends toward the classical. Its open roof is most often supported by a colonnade (a row of columns). Originally the construction was a wood projection carried by a single row of columns from a masonry wall—the definition of the Latin word pergula. Similar garden structures were revived during the Italian Renaissance of the 16th century, and eventually they spread with the Classical Revival to England.
The modern pergola developed from the “covert walks” of the great English gardens of the 17th and 18th centuries. During the late 19th and early 20th centuries, pergolas were touted by English landscape greats, including Gertrude Jekyll. The American heyday of the pergola came during the golden age of gardens, 1890 to 1940. They are evident in photos of the great country houses by such early 20th-century architects as McKim, Mead & White, and in the landscape designs of the Olmsted firm.
Two main types are the pergola-porch, an attached structure with an open roof, and the pergola-arbor, a vine-covered walkway leading to the front door or out into the garden. The pergola-porch (or covered patio, or window shade) offers practical advantages. During the winter, the open roof permits low-slanting sunlight to enter—especially important for bungalows with their dark, overhanging eaves. In summertime, the vine cover provides shade. Pergola-porches could extend across the front of the house, like a veranda, or be added to the side as a sun parlor or an outdoor dining room.
Pergolas were especially popular for houses built along the coast. They were used to mark property lines, and as a screen between the house and the street. A pergola built on a curve created a lovely backdrop for a reflecting pool.
By 1905, the pergola had become a mainstay of Arts & Crafts designers; Gustav Stickley published entire articles on their stylistic possibilities as well as their moral value (to calm an “overwrought” society, to introduce healthy children to nature) in The Craftsman magazine.
A pergola is most likely to reach old age when the piers or columns are masonry rather than wood. Maintenance is constant, particularly in regions with cold winters and lots of rain. Eager to bring back the old gardens and heirloom roses of their 1915 landscape, one family who inherited the original pergola has the wood structure repaired, scraped, and painted as needed—every year.
New materials have entered the mix. Columns are now available in manmade stone—a weatherproof matrix of resin, fibers, and stone dust. Components are made out of cellular PVC. Building a pergola from a combination of modern materials and wood may be the best choice, offering longevity for structural parts along with traditional elements that will weather attractively.
Built to Last
A pergola’s one-with-nature construction is its appeal and its downfall. Covered with plants, unable to shed water, these structures are high-maintenance. You won’t find many originals still standing.
Generally, a pergola consists of columns, posts, or piers supporting hefty beams or doubled plates, which in turn support rafters (and sometimes vine strips or latticework). The rafter ends were quite often sawn into fancy shapes for classical and Arts & Crafts-style pergolas.
Today, you can build a pergola of pressure-treated lumber. Follow all the best-practice standards for exterior carpentry. Columns should rest on stone or concrete footings that extend below the frost line. Wood columns must be anchored to the footing, typically with tie-rods running inside the column shaft to a steel plate in the cap. Flash caps or capitals before installing beams or plates.
Horizontal plates (parallel 2x6s or 3x8s) are usually bolted to the column or, for piers, into an anchor plate mortared into the masonry. Rafters are 2x4s or 3x8s set on edge, spaced 24" to 30" apart and anchored to the beams with metal straps or plates. Companies that manufacture and install traditional wood fences do pergolas, too.
A pergola has pleasing proportions when its width does not exceed its height, and when its rafter ends have a sense of uplift. Length, of course, can vary. Typical columns are 8' or 9' tall and spaced about 8' apart. Consider a “floor” rather than grass, which won’t thrive in the shade; use compacted stone dust, brick pavers, concrete, or (in some climates) tile. Common plants for pergolas include roses, wisteria (which will eventually tear apart all but the sturdiest structure), honeysuckle, grapevine, ivy, and morning glory.