Privet makes a dense evergreen hedge, but it can grow too large or thin if not pruned regularly. You can choose from several varieties with different leaf shapes and colours, but all thrive under severe pruning, so you can keep them the size of hedges or let them grow to small trees. Variegated Chinese privet has small whitish or yellow leaves, while Japanese privet has dark green, glossy leaves. Both produce small clusters of white flowers in the spring.
Prune a newly planted privet hedge six inches high, according to the Maryland Cooperative Extension Service. Use sharp pruning shears and cut each branch off level—not at a slant—slightly above a bud or side branch.
Prune the new plants again when they've added six to 10 inches of new growth. Cut back most of the new growth, leaving only a couple of inches of new growth plus the old growth. Continue until the plants reach the height you want for the finished hedge.
Shear privet several times during the growing season to keep it in a formal shape, using pruning shears or a hedge trimmer. Cut off small branches that have grown beyond the boundaries you want. If you're creating a hedge, shape the plants so the base is wider than the top to allow sunlight to reach all of the hedge.
Remove dead or diseased branches or perform other major pruning after the plants have gone dormant for the winter.
Cut back privet severely to renew an old hedge, using a pruning saw, shears or a chain saw. Cut it back as low as 12 inches from the ground after it has gone dormant for the winter, then treat it as a new hedge for the next year or two, pruning it to encourage a wider base as you gradually let it reach full size.
If you're pruning diseased plants, dip the blade of shears or a pruning saw in a disinfectant between each cut, to prevent spreading the disease, according to Erv Evans, consumer horticulturist at North Carolina State University. He recommends 70 per cent wood alcohol or a disinfectant made of one part bleach to nine parts water.