Boxwoods are famous for their use in formal gardens, on historic estates such as Colonial Williamsburg in Virginia, or the Biltmore House in Asheville, N.C. Boxwoods have a multitude of uses in the landscape and are frequently utilized as hedges, screens and specimen plants. They are sensitive plants, but they will thrive if given the right growing conditions.
There are two types of boxwoods used in landscapes in our area: littleleaf boxwood (Buxus microphylla) and the common or American boxwood (Buxus sempervirens). The littleleaf boxwood is a low growing compact shrub. It has bright green lance shaped leaves that turn bronze during winter. The American boxwood is a wide shrub that grows up to 10 feet tall. The oblong to oval shaped leaves are dark green above and light green beneath. It is more cold tolerant.
Boxwoods can grow in full sun but prefer part shade. They require well drained soils. Avoid placing them near downspouts or other areas that stay wet. Since the plants have shallow root systems, plant them no deeper than the top of the rootball.
They should receive adequate amounts of water to encourage the development of a healthy, well branched root system. Place two to three inches of pine straw or pine bark mulch on the ground under the shrubs. In the early spring, uniformly spread an all-purpose fertilizer, such as 10-10-10, over the root zone.
Boxwoods are slow growing shrubs, usually less than a foot per year. They produce a majority of their growth from buds near the end of their branches forming dense foliage on the outside of the plant and very few leaves inside. The thick foliage decreases air flow, which can lead to various plant diseases.
Thinning is the process of removing selective branches to allow for improved light and air penetration. Spring is the best time of the year to perform this task. Periodic light to moderate pruning is the preferred method during the rest of the growing season. Avoid shearing boxwoods or engaging in heaving pruning. The plants regenerate new growth at a slow rate and are slow to recover.
If you have a boxwood that you would like to shorten the height, this can be done over a period of a few years. In the first year, prune one-third of the tallest branches to the desired height. In the second year, cut back half of the remaining branches and then prune the remaining branches in the third year. Dead or diseased branches can be cut out at any time.
One common pest is the boxwood leaf miner. They are small flies, which lay their eggs in the leaves during the spring. The larvae are small and orange in color. They feed inside the leaves where they overwinter and emerge as adults the following year. Certain insecticides, such as Bayer Advanced Tree and Shrub Insect Control, Ortho MAX Tree and Shrub Insect Control, and others can be used to control the leaf miners. Please make sure you follow all label direction and safety precautions when using pesticides.
Boxwoods will prosper if planted and maintained properly. They can add beauty to both formal and informal landscape plantings.
Timothy Daly, MS, Agricultural and Natural Resource Extension Agent, Gwinnett County Extension. Contact him by phone at 678-377-4010 or by email at firstname.lastname@example.org.