Topiary is the art of decorative sculpting with living plants. Topiary trees can be created by pruning dense shrubbery like boxwood into ornamental shapes or by shaping forms from wire, filling the wire forms with sphagnum moss, and planting the moss with vines that will grow to twine around the form. The art of topiary is as least as old as the ancient Roman Empire and is practiced today all around the world.
According to the UK's Topiary Organisation, an international association of topiarists and suppliers, topiary was first written about in ancient Rome between 38 BC and 14 AD, but had likely been practiced well before then throughout the Mediterranean and Asia. Topiary faded in the dark ages and experienced a rebirth in the Italian Renaissance of the 14th century.Topiary experienced its golden age in the estate and castle gardens of the 17th century.
Traditional boxwood topiary spread from the Roman Empire through all of Europe. Topiary enthusiasts have devised other ways to grow topiary far beyond the growing range of the box (Buxus sempervirens). The Topiary Organisation reports that topiary fruit trees and roses are popular in Iraq, that North Americans have adapted topiary to new wire forms, and that a topiary garden graced the grounds of the Beijing Olympics.
The two primary types of topiary comprise a single large bush that has been trimmed to the topiary artist's desired shape and topiary grown on wire forms. Topiary trees can be cut from single bushes and are often formed from a dense-leaved bush that has been grafted onto a tall, straight trunk from another bush variety. Wire-form topiary trees start with a ball of wire placed on top of a tall stick or dowel in a lollipop shape. The ball of wire is filled with damp sphagnum moss, and then green moss or small vines are planted in the wire ball to grow and twine around it.
Outdoor topiaries are large--several feet in each direction--to allow for the growth of a mature shrub suitable for trimming into shape. However, the wire-form type of topiary is considerably more adaptable to different sizes, especially if green moss or a small-leaved vine is used. Topiary trees can be as small as just a few inches high to serve as a table centerpiece or many feet tall to serve as a whimsical fantasy garden tree. Smaller wire-frame or container-grown boxwood topiaries must be watered and fertilized frequently to maintain their lush appearance.
Traditional topiary was an aesthetic complement to a formal garden setting. The University of Illinois Extension service suggests that today's topiary is more about whimsy and creative personal expression. Wire-frame topiaries can be used to create a menagerie of garden animals or mimic classical sculpture. Consider using unique plants to accent your topiary, such as spiky hens and chicks or tufts of small ornamental grass, gray-leaved creeping thyme, or the red or golden leaves of stonecrop sedges.