A hedge around the perimeter of an herb garden is a definitive edge, a wall of green that can confer an invaluable sense of privacy and intimacy, a screen against the outside world that’s every bit as effective as a stone wall. Tall hedges such as the ancient, towering evergreen hedges of yew or box in older European gardens transform the garden into a quiet room of beauty and solitude for an afternoon cup of tea or a secret tryst. A lower hedge can visually frame the garden space as though it were a picture.
But a hedge contributes more than aesthetics. A tall hedge bordering the garden where it interfaces a street will help hide the sight and muffle the sound of traffic and other unpleasant reminders of the world outside the garden. And a hedge offers protection from the wind, enclosing and concentrating the scents of the herbs so that they don’t drift away on a passing breeze. Not only will the gardener enjoy the fragrances at their most potent here, but the calm, scented air will attract the butterflies, bees, and other insects that are among the garden’s most valued visitors.
Choosing plants for a hedge
Herb hedges are a long-standing tradition, best known in history in European knot gardens of the sixteenth and seventeenth centuries. Many herbs lend themselves to low hedges, but few make decent tall or medium-sized hedges of 3 feet or more. In the mildest climates of the South or California, upright rosemaries serve well as intensely fragrant hedges (see photo above), to be lightly clipped or left to branch naturally, 6 feet or higher; myrtle, bayberry, or even bay may form a robust screen in mild climates. We who garden in cooler regions, however, have few options for tall evergreen herbal hedges. We must settle for herbaceous perennials which die down in winter, or look beyond the rather elastic category of “herbs”.
In choosing plants for a hedge, look around at hedges in your area and talk to other gardeners, local landscapers, extension agents, and the staff of garden centers. Tall hedges that are frequently used to enclose herb gardens include yew, holly, hemlock, boxwood, arborvitae, and lilac.
Because capturing the fragrance of the herbs is one of the main purposes of a hedge, pay particular attention to the scent of the hedge itself. The sickly scent of privet flowers, for example, can be unpleasant, and the fragrance of boxwood is offensive to some people. Professional gardener Lauren Springer suggests osmanthus, or holly olive (Osmanthus heterophyllus), a glossy-leaved shrub of the olive family that grows in light shade or full sun and is hardy to Zone 7. Its small white flowers, emerging in fall, have a strong jasminelike scent that complements the fragrances of the late-season herb garden.
A formal hedge can be a considerable investment in time, money, and regular maintenance. Some hedge plants, such as box, may take years or decades to grow tall enough to be an effective screen, so the hedge fancier must either have patience and a long-term vision or pick a faster-growing species. And tall hedges can screen out the sun even as they conceal the neighbor’s yard. If your space is limited and sunshine is at a premium, a low hedge may be a better bet.
For a faster-growing and less demanding natural barrier, a tall, dense border of herbaceous perennials may accomplish many of the same aims. James Adams suggests fragrant screens of tansy, fennel, meadowsweet, valerian, giant alliums, and white mugwort. These tall herbs will do best in full sun or partial shade and should grow under a wide variety of conditions.
The hedge you choose to grow, whether it serves as a fence or a simple border, will add beauty and order to your garden edges.
— Kathleen Halloran, health and environment reporter for the daily Coloradoan in Fort Collins, Colorado, is designing the herb garden for her new home.