Creating Privacy Barriers with Shrubs by Barbara Blossom Ashmun
As a garden designer, I help homeowners improve their gardens, and often the most important need is for greater privacy. Many gardeners also express a desire to have a more intimate garden, a place to sway in a hammock and enjoy solitude, or share an iced tea and conversation with a friend. The most cost-effective way to give the garden greater shelter, and divide large spaces into cozier nooks, is by growing green walls.
Walls of stone, brick or stucco could accomplish the same ends, but at far greater expense. Living walls have added advantages beyond economy: the beauty of their foliage color and texture; their seasonal displays of colorful flowers and berries; their usefulness as bird and butterfly habitat; their benefit as a source of cut greens for bouquets, wreaths and mantle displays.
With so many plants to choose from, the first quality to consider is the shrub's ultimate size in maturity; its height and spread eight-to-ten years down the line. On small properties where only a few feet of space are available for a hedge, columnar shrubs with small leaves or needles that can easily be trimmed are more compatible than large, arching bushes that will quickly outgrow the area. Where there's plenty of room, larger, fast-growing shrubs will give you immediate gratification and you can let them spread to their mature size without clipping. Consider also whether it's really necessary for your screen to be evergreen. In places where the privacy barrier is important in all four seasons, stick to evergreens, but in locations where you'll be spending time mainly in summer and fall, broaden the choices and select deciduous, flowering shrubs for added color and fragrance. A hedge of 'Hansa' roses (hybrid rugosas) with sweetly scented magenta flowers and red autumn hips is unsurpassable.
An easy way to determine the desired height of your privacy barrier is to have a friend hold a yardstick and pretend to be your hedge. Ask her to raise the yardstick until her height plus the yardstick's length hide the scene that you want to screen. If a six-foot-tall shrub is enough to hide the neighbor's compost pile, you can begin your plant search with that size in mind. If you're trying to blot out a bright yellow play structure, you will probably have to choose taller shrubs or trees, and the yardstick trick will help you figure out just how high is enough.
Many of the needle evergreens including yew, arborvitae, hemlock, and incense cedar make fine hedges. Garden designer Elizabeth Marantz, whose large Portland garden is divided into several spaces, favors Hick's yew (Taxus media 'Hicksii') for its handsome, fine-textured, evergreen foliage. The red yew berries are also decorative until the robins eat them (seeds are poisonous to humans).
Low maintenance is another advantage because Hick's yew is relatively slow-growing you only have to prune it once in late summer. Marantz prefers long-handled Japanese hedge shears which let you stand back from your work and clip away. In spring the new growth is chartreuse, and to emphasize that she grows chartreuse-flowering cushion spurge (Euphorbia epithymoides) , swamp spurge (Euphorbia palustris), Corsican hellebore (Helleborus argutifolius) and bearsfoot hellebore (Helleborus foetidus) nearby. It took about four years for the 2-gallon starter plants to develop into a chest-high hedge. In the past visitors would wander down her hillside beckoned by a view of Mount Hood; now the hedge screens the alluring meadow and guides them to the front door. For a bigger hedge where you might need a ten-to-fifteen-foot tall screen, Marantz likes Portuguese laurel (Prunus lusitanica), a broadleaved evergreen with serrated leaves in a rich shade of dark green. Left alone it will form a multitrunked spreading tree; clipped it shapes up nicely into a hedge. It grows more slowly than English laurel (Prunus laurocerasus) and has darker leaves that recede modestly into the distance compared to English laurel's shiny yellow-green foliage that jumps out visually.
Seattle-based landscape architect Terry Welch transformed columnar junipers (Juniperus communis 'Stricta') into a slender, four-foot-tall, blue-green wall that guides you down the path to his Japanese-style entry garden. Even though it's a lot of work, Welch willingly clips the junipers several times a year because the shapely "blue cigars" are a whimsical touch that everyone loves. Within his entry garden he established a four-foot-tall wall of clipped boxwood to separate the benches where he grows bonsai from a sitting space with a table and chairs. The boxwood is tall enough to provide a feeling of shelter while you're sitting down, yet low enough so that you can enjoy glimpses of the beautiful bonsai beyond the hedge. Boxwood can also be allowed to develop into a taller wall with judicious clipping to control its width, or to billow into a large evergreen shrub for a more informal look. Similar in leaf size, but darker green in color, convexleaf Japanese holly (Ilex crenata 'Convexa') can also be clipped into a strict wall or allowed to expand into a spreading screen, about five feet around.
The same is true for many flowering broadleaf evergreens. Let them grow into their fullness where space allows (I like them best this way) or clip them into walls if you must restrict their size. Where there is enough room, andromeda (Pieris japonica) forms a tall natural screen in sun or shade, eventually growing twelve-fifteen-feet tall and eight-foot across. Fragrant white flowers that look like lily-of-the-valley make a showy spring display. Sun-loving Cotoneaster franchetii , with tapered blue-green leaves, arches gracefully to display lacy flowers in spring and clusters of red berries in autumn. Unclipped it will occupy at least eight feet around, but it can easily be clipped into a narrower shape.
Early pink buds that open to creamy white flowers followed by blue berries make evergreen Laurestinus (Viburnum tinus) a popular choice for dense screening. Left alone, shrubs will grow eight feet tall and wide; 'Spring Bouquet' is said to be more compact, closer to six feet. Mexican orange (Choisya ternata) is another good hedging plant, with glossy trifoliate evergreen leaves that release the fragrance of orange peel when pruned. Without clipping the shrub will grow ten feet tall and eight feet wide, but the flexible branches can be reduced to any size. I prune mine with hand-held Felco secateurs in late spring after the white, lightly scented flowers have embellished the handsome foliage. This plant does well in sun or shade, and although commonly available, is uncommonly attractive.
For complete shade my first pick is the taller form of sweet box (Sarcococca confusa) with small tapered leaves of a glossy dark green. In February the small white tasseled flowers will send such a piercingly sweet scent into the garden that you will think spring has arrived.