Pruning privet hedges is essential to maintaining their shape, overall appearance and health. Pruning privets is easy because you don't have to pick and choose which stems to cut and which ones to leave alone like you do when pruning other types of trees and shrubs. You can simply make level, clear cuts to keep the privet hedges looking neat and healthy. The hardest part of pruning privets is making even, level cuts, but there are tricks to help guide you in doing this.
Prune your privet hedge in early spring. Once-per-year pruning is usually sufficient for privets, but you can prune again in late summer if needed. A good rule of thumb is to cut back stems 6 inches every time they grow 1 foot.
Trim the sides of the privet hedge first. Using a hedge trimmer, pair of pruning shears or loppers or a power trimmer, trim back the sides of the privet hedge, angling slightly outward as you trim from top to bottom.
Insert two wooden stakes or poles into the ground on either side of the hedge (lengthwise) and slightly in front of the hedge. Make sure the stakes are the same height as or slightly taller than the hedge.
Tie a string between the two poles, standing back and adjusting the string until it is level. Keeping it level, lower the string until it is at the desired level to which you are trimming the top of the privet hedge. The string will be your guide for trimming the hedge's top evenly.
Trim the top of the hedge. Use a single, sweeping motion to trim back the top. Stand back and inspect your hedge to make sure that you have the desired shape.