Choose the type of tree or shrub based on the required height of the privacy hedge. Figure out the desired width of the privacy hedge and dig a hole twice the diameter and the same depth as the root ball. Place a tree or shrub in the hole and fill the hole with soil, then water thoroughly. Space trees or shrubs from 12 to 24 inches apart, center to center.
If the privacy screen is required year-round, evergreen trees or shrubs are a better choice than deciduous plants, since they do not lose their leaves. For evergreens, arborvitae and boxwood are excellent choices, according to ArborDay.org.
Once the shrubs have been selected, map the location of the hedge a place a wooden stake at each end. Tie a string to each of the stakes and use the string as a guide to keep the hedge row straight. After this, each of the hole locations can be marked using a sprinkler flag or an additional stake. After one to two seasons of growth, the trees or shrubs will be fully established and require training. Trim the tops and sides of the hedges to the desired height or width, being careful to only remove half the length of new shoots.