when should i trim a japanese holly hedge and boxwoods? the holly hedge will...
Japanese holly usually withstands severe pruning. The best time to prune is in the spring and you may need to touch up in June or July after the new growth hardens off.
There are several types of pruning methods for boxwoods. You did not mention what your goal is. The best method for pruning English boxwoods is thinning. This allows the center of the plant to receive adequate sunlight and good air circulation. The best time to thin boxwoods is December through February. The temperature should be above freezing.
Shearing - An example of this is if you are growing boxwood as a hedge. Best time to shear is in early June. A second light pruning may be needed in July. If reducing in size drastically, this requires a two step approach and should be done in the early spring.