Pergolas and Arbors are often confused as meaning the same thing, but there are distinct differences.

PERGOLAS

A pergola is a garden structure forming a shaded walkway, passageway or sitting area of vertical posts or pillars that usually support cross-beams and a sturdy open lattice, often upon which woody vines are trained. They can provide shelter, privacy, or act as an accent. It can also blend or separate different garden areas, direct traffic, and support plants.

I use the term pergola when I design such as structure that is more rectangular than square and serves more as an open beam passageway with sturdy columns or posts that accentuate the linearity of the space.

This pergola (above) is distinct from an arbor as it functions as a passageway.

ARBORS

An arbor is often used synonymously with the term pergola because both serve to serve as a covered passageway that supports the growth of vines.

Typical Arbor

Typically however, an arbor is a much smaller version of a pergola often with only one or two posts or columns and can sometimes have a bench for sitting. Arbors tend to have trellises or latticework along the sides to help support the growth of vines to the overhead rafters.

Both pergola and arbors could also be attached to a building. Arbors can be made from wood or wrought iron, and can be made or bought at a garden center or an online catalog.

Arched arbor with trellis latticework

PATIO COVERS

Part of the confusion about what defines an arbor and a pergola since they were first used in Europe is that their designs have overlapped in terms of purpose, function and design. Over the centuries, their names have been used to mean the same thing, but in the classical sense, the do both have separate architectural definitions if you want to be technically accurate.

Patio Cover – Free Standing

Personally, as a landscape designer, I tend to describe my structures in terms of whether they are open beam rafter style or solid covered roof style. As such, the generic term “patio cover” simply means a patio with a covered structure regardless of whether it has solid roof or not. Solid cover, free standing garden structures consist of Gazebos, Ramadas and Pavilions. 

TRELLIS

A trellis is a latticework typically of wood or metal that provides a climbing support for vines. They can be free standing to serve as a fence or decorative panels or they can be attached to walls for fences or the sides of a building.

Pergolas, Arbors, Patio Covers and Trellises can add significantly to defining outdoor space by creating shady sitting areas, walkways and overhead canopies for various kinds of patios. They are considered part of the “hardscape” of a garden versus the “softscape” which refers to the trees, shrubs and flowers.

Here is a Flickr Slide Show of Pergolas, Ramadas and Arbors.