What Exactly Are They?

Arbors

Technically, an arbor is an open framework structure that forms a shelter, gateway framework or bower. Its primary purpose is to be a semi-architectural place for climbing plants to grow, while providing shaded seating, directional form to frame a view or to create a private out-of-doors area.

An arbor can be arched or square-topped. It can be constructed out of materials as diverse as metal, rustic logs, light-weight concrete, milled and painted lumber, stone and mortar, bundled twigs, bamboo or even molded plastic. You can make one yourself or purchase pre-constructed arbors. An arbor differs from a gazebo in that its roof area is open to the elements, while a gazebo traditionally has a solid roof that protects those seated beneath it from the elements.

Trellises

Trellises are also light-weight elements used for controlling the shape or to support climbing and other plants. In most instances a trellis is usually constructed on a flat plane, in a two-dimensional way, unlike an arbor, which is frequently a three-dimensional structure.

For instance, a trellis may be no more complex than a grid of cable or heavy wire stretched and anchored across an existing brick wall or board fence. A trellis can also be constructed as a series of open grid panels that are secured to posts and function like a fence.