Ligustrum shrubs, most commonly known as privet shrubs or hedges, can be trimmed at any time of the year, according to SFGate Home Guides. Pruning is used to size and shape the shrubbery, encourage new growth, thin the shrubbery's interior and remove dead or diseased foliage.
There is a wide variety of ligustrum species and cultivars, some of which can be used as small trees in the landscape. Although ligustrum is most often grown as shrubs or hedges, privet trees are also popular because they grow quickly, meaning they require proper pruning. Privet tree cultivars can be deciduous, evergreen or semi-evergreen.
Clemson Cooperative Extension states that Japanese privet trees have a rapid growth rate and reach a mature height of about 10 feet. The trees can be pruned throughout the year. Semi-evergreen options include the California privet, which reaches a mature height of about 15 feet, and requires consistent pruning at warm, humid sites. Since ligustrum trees have such a rapid rate of growth, and because they produce abundant foliage, they need to be consistently trimmed to result in a healthy, strong privet tree. Privet trees can also be heavily pruned, if desired, to create a desired profile and shape.