What you’ll need
step 1: Think About What You Want the Hedge to Do
Think about why you want a hedge and what job it will do in your garden. It may be a wall to give you privacy from the street or a low barrier to discourage traffic across your lawn. Think what it should and shouldn’t do, then decide what minimum and maximum heights will work. For example, the minimum height for a privacy screen may be eye-height so people can’t see over it, and the maximum height may be 7 feet because any higher would make you feel walled in.
step 2: Select a Hedge Plant
From garden books or your local garden center, select a hedge plant that will do what you want it to do. Boxwood and yew are the most frequently-chosen hedges, but dozens or hundreds of trees and bushes can be made into hedges. Think about the size you want and select a plant you can keep within that size range. If you want to prune it with hedge shears, select a shrub with small leaves or needles.
From the garden book or garden center, see how far apart to plant your hedge shrubs.
step 3: Dig Holes or a Trench
If the plants are small and will be planted closer than 18 inches apart, dig a trench where the hedge will be. Make it the depth of the root balls, and twice as wide as the root balls. For plants that will be spaced more than 18 inches apart, dig individual holes as deep as the root ball and twice as wide.
Add about 1/3 as much organic compost as you have loose soil. Sprinkle slow release plant food on the soil and mix it all together.
Remove the plants from their containers and set them in the holes or trench. Check the depth of the hole to make sure the surface of the root ball is at ground level. Backfill the loose soil around the root ball and use some of the soil to make a low dam around each root ball. Water the plants in by filling the area inside the dam with water. Let it soak in, fill it again, then rock each plant a little to release bubbles and settle it into place.
When they are through draining, smooth the soil around them and mulch them with 2 to 3 inches of mulch.
step 4: Train the Hedge
Let the hedge plants grow for a year without pruning. This unchecked growth gives their roots a chance to grow as strong as possible. The following spring, cut the plants back to 6 inches high. As they regrow, shear them lightly, removing only 1/2 inch of growth, whenever they have made 4 inches of new growth. The shearing will make them bushy and shape them as you want without restricting their growth unnecessarily. Feed them with more Osmocote and refresh the mulch.
Continue this training until the hedge reaches the minimum size you selected, then change your pruning practices. Each time you shear, cut them back almost to the last cut, leaving only 1/4 to 1/2 inch of growth. This slows their growth, keeping them within the size range you’ve selected for as long as possible. The small amount of new growth you leave each time keeps them healthy. If you cut them back to the same place each time, eventually they will develop thin and bare spots in the foliage.
After several years, when they reach the maximum height you selected, cut them back to their minimum height in early spring and let them begin the growth process again.