What is the difference between a pergola and an arbor? If you look up the words in an on-line dictionary you will find arbor defined as something like, “A shady resting place in a garden or park, often made of rustic work or lattice work on which plants, such as climbing shrubs or vines are grown” (The Free Dictionary by Farlex). A pergola is defined as, “An arbor or passageway of columns supporting a roof of trelliswork on which climbing plants are grown.”

Landscape design writers such as Gordon Hayward and Cynthia Cash define the strict usage of the work pergola to refer to a colonnade or passageway.  About.com quotes Cynthia Cash, ”The primary difference in an ‘arbor’ and a ‘pergola’ is that an arbor is a free-standing structure (also used to support vines), whereas a pergola is a long linear structure over a garden pathway.”

Judging from images pulled up using Google, common usage of the word pergola defines it as a “substantial” columned structure which can either be over a walkway or, more commonly, over a sitting and dining space adequate for a group of people. While this could also be called an arbor, the word arbor is generally reserved for smaller structures over gateways or individual benches. Both arbors and pergolas are used as a structure to support climbing plants.

No matter how you use the words, arbors and pergolas are important elements to define, soften and divide both small and large spaces. Arbor gates create a defined transition between “outside” the garden to the intimate interior. They also frame a view into the garden at this threshold. A pergola’d sitting area, either attached to the house or freestanding, creates a defined outdoor room as well as breaking up horizontal lines of fences and garages.