It's surprising how versatile a hedge can be. For practical purposes, a hedge is a means of barring trespassers from your property, blocking out an ugly view or serving as a shield against the wind. But there's more to a hedge than a row of plain old privet or barberry or a wall of hemlocks.
Slip in instead purple-leaved Sand Cherry with its eye-catching foliage accented with white blossoms and deep purple fruits, or Leland cypress, the new Red Pygmy barberry, or even flowering azaleas, and you gain extra mileage -- decorative value.
The specifics of hedges were recently discussed at a slide lecture at Brookside Gardens in Wheaton. Providing insights was Rebecca Zastrow, a staff horticulturist there.
An enclosure of hedges, she says, can turn an open space into an outdoor room, or provide privacy for a secluded spot. Cut-outs in a hedge make peep-holes, lending the garden view an air of mystery. As a backdrop for a bench, a hedge adds to a feeling of intimacy and coziness. A hedge around trees or shrubs keeps the ground lodging their roots from being trampled and packed down, which deprives the roots of air.
A hedge can also conceal utility equipment, soften the harsh features of a chain-link fence or substitute for one, or separate a house from a driveway or direct foot traffic.
Privet, Ms. Zastrow says, is the least expensive and easiest to grow, but it will also keep you the busiest controlling its shape. It is also the "greediest" hedge, robbing other plants in its vicinity of food and moisture, she says. For that reason, she says, don't plant privet behind a flower bed.
For an informal hedge, Ms. Zastrow suggests forsythia as one possibility. It brightens the garden in spring with its cheery yellow flowers and offers the appeal of gracefully flowing branches. To shear them into a tight mass or square them off destroys the plant's character. Shortening branches when they extend beyond their bounds is usually trimming enough for forsythia. If left untended, however, it becomes overgrown, and thinning out or cutting back to reduce height and density may be needed.
As a simple boundary marker where the lack of uniform growth wouldn't matter, day lilies or ornamental grasses create an out-of-the-ordinary hedge, Ms. Zastrow says. To play up an entrance, Ms. Zastrow proposes Japanese holly or taxus (otherwise known as yew). For screening a utility box, she mentions sycamore or maple trees. A Nellie
Stevens holly or taxus, she adds, also makes a good backdrop for a perennial border.
The spacing of plants in a hedge is as critical to its well being as is the method of pruning. You can set plants single file or stagger them in a double row. The degree of separation will depend on their size and the speed at which you want them to fill in. In general, Ms. Zastrow says, the distance between plants in a hedge is usually 1 to 3 feet. For hollies, it increases to 4 feet.
White pines might need as much as a 1O-foot allowance. Because they are not pruned and their branches don't meet the ground, these trees are not considered true hedges. In the case of Leland cypress -- which are naturally narrow -- the closer you put them the sooner they'll knit together.
To determine the number of plants you'll need for a given row of hedge, divide the length of the row by the spacing between the plants. A 20-foot row of abelias set on 2-foot centers, for example, would require 10 plants.
The style of pruning, Ms. Zastrow adds, depends on the plant and the effect you're after. An informal hedge won't need much more than tidying up and the removal of old canes. A formal hedge, on the other hand, such as boxwood or ilex Convexa, will require close cropping.
The appearance of a hedge can be easily ruined by improper clipping. Cut it on a slant, therefore, so the bottom will be broader than the top. The lower branches will thus be exposed to sunlight, without which foliage will die and the base of the hedge will be left bare.
For more about hedges, "Hedges & Shrubs" (Ortho Books, $7.95) will fill you in on many details.