Four 'Emerald Green' arborvitae, which will eventually reach 12-15 feet tall, are a good choice for a four-season privacy planting in USDA Zones 2 to 7. In the foreground, a 'Green Mountain' boxwood can be easily maintained at 3 to 6 feet.
Mix Things Up
Rather than planting multiples of the same shrub or tree for a consistent border, consider creating a mixed border using a variety of shrubs and trees, evergreen and deciduous. You'll be able to have seasonal color, the flowers, berries and forms of your choosing. More importantly, you'll be reducing the chance that a pest or disease can wipe out the whole planting.
Sprucing Up the Patio
Spruces comes in many tones of blue or green and in almost any height, including the 60+-foot Colorado blue spruce. But consider a dwarf version, such as the slow-growing five-foot 'Globosa' as an accent for the patio border.
Screen and Groundcover
Bottlebrush buckeye. This deciduous shrub grows up to 12 feet tall and expands via suckers to 15 feet wide. Its showy flowers appear in mid summer, and fall foliage is often a landscape-brightening yellow. Bottlebrush buckeye suppresses growth of other things in its shade, so it's a good choice if you want to block weeds and gain three-season privacy.
Bit of a Border
An ivy-covered fence creates a low wall for this outdoor room. Japanese holly 'Compacta' or 'Manhattan' euonmyus would be other good choices for an easily-maintained four-foot hedge.
Summersweet, or clethra, grows to five feet tall and about three feet wide. In late spring to early summer, delightfully fragrant flower clusters can perfume your outdoor room. During the rest of the growing season, the leathery green leaves do a good job of setting low boundaries (or taller ones, if you plant it on a slope above the sitting area).Image courtesy of Proven Winners
Feathery, Three-Season Screen
This fine-textured perennial works well as a patio plant or in the ground, where it can achieve an average height of 5 to 7 feet. At only three to five feet wide, it's a great choice for tight spots. The fernlike foliage turns yellow in fall, then dies back. Give this plant sun or partial shade and well-drained soil. Unlike its cousin, buckthorn, 'Fine Line' isn't invasive. Note: The berries aren't edible. USDA Zones 2 to 7
— image courtesy of Proven WinnersPhoto courtesy of Proven Winners Image courtesy of Proven Winners
For gardeners in frost-free zones, Egyptian papyrus 'King Tut' creates a dramatic focal point for the pond's edge or patio; the grass-like plant reaches 4 to 7 feet tall. Give this plant moist to wet soil, but if the temperature dips below 35 degrees F, kiss this plant good-bye and plant a fresh one in the spring.
— image courtesy of Proven Winners