The advantage of hard pruning is that the shrub rejuvenates quickly. Gardening: How to grow and maintain boxwood well; Treatment: fight against the boxwood moth; Period for pruning boxwood Aiming below the ultimate height I want the shrub to be. Rejuvenation pruning and renewal pruning are two techniques that can reduce the size and volume of many shrubs without unduly harming them. Mature boxwoods, shrubs that are more than three-seasons old, need heavy-duty pruning. Check for signs of pest or disease problems as well. Tree pruning is best used to remove excess branches, prevent branches from rubbing, remove broken branches, remove double leaders, and remove narrow v-shaped crotches. Using a bypass pruner, reach inside the shrub down to about 6 inches and prune off a few of the inner stems. This form of pruning is required besides the ornamental clipping discussed above. Most broadleaf shrubs (such as azaleas, camellias, ligustrum, abelia, nandina, cleyera and crape myrtle) respond well to renewal pruning. Renewal pruning should result in abundant new growth by mid-summer (Figure 9). Introduced to America in 1652, boxwood shrubs have been gracing gardens since colonial times. Stage-wise Pruning. This technique is called renewal pruning. Pruning a boxwood is a gesture which allows both to model this magnificent shrub while allowing it to renew its foliage and to become denser. Gradual rejuvenation allows you to remove old branches over a period of three years. There are two basic approaches to handle pruning of mature boxwoods: 1. The best time to thin boxwoods is December through February. The temperature should be above freezing. Which is more appropriate in a given situation will depend on the plant species, the shrub’s function in the landscape, and the wishes of the property owner. A single, intense pruning season creates unwanted stress on the shrub. Although it is slower than hard pruning, shrubs that are rejuvenated over a period of time look better in the landscape as they regrow. So there may be some trees nearby that have grown too large and need some pruning of their own this winter to help the boxwoods be their fullest. This allows the center of the plant to receive adequate sunlight and good air circulation. Boxwoods, because of their dense foliage, often die out in the center from a lack of sunlight. Seasonal Pruning. Boxwoods are the exception and I do not recommend renewal pruning them. Members of the genus Buxus include about thirty species and 160 cultivars, including Buxus sempervirens, the common American boxwood.The varieties are largely based on leaf size and growth which can range from one foot tall to twenty (.3-6 m.). About one-third of the bush should be thinned each year, since boxwoods keep their foliage for three years. Heading Back Thinning reduces size & improves light penetration. Shearing - An example of this is if you are growing boxwood as a hedge. The best method for pruning English boxwoods is thinning. Anytime, Renewal prune in spring: Boxwood : Anytime-July: Buddlia : Early spring, 6″ from ground: Caryopteris : Early spring, 6″ from ground ... And, renewal prune removing the oldest stems out at the ground level: Maple shrubs : Anytime: Mockorange : Immediately after bloom, Can be cut severely : … Narrow-leaved evergreens, such like junipers, cypress, and cedars, should never be renewal pruned. And, of course, the healthiest plants are the ones that are going to take a hard pruning … Don't be afraid to prune it, it also gives it more vigor! Renewal Pruning of Shrubs Good candidates for renewal pruning Alpine Currant Amur Maple Potentilla Barberry Flowering Almond Boxwood Chokeberry Clethera Cononeaster Honeysuckle Maintenance areas to watch Maintenance Thinning vs. The way I was trained to hard prune boxwood was to take the tallest stems and cut them way down into the plant to a branch fork. Once the new shoots are 6 to 12 inches long, prune the tips to encourage lateral branching and a more compact shrub.