Boxwoods (Buxus sp.) are a well-known garden shrub frequently planted in Georgia.
They have been used for many years in English formal gardens where they gained the reputation as a must-have for upscale, magisterial landscapes.
Boxwoods are often used to frame the straight lines of houses and walkways. Although boxwoods can be successfully grown in Georgia, proper management can be difficult.
Following are some tips to help your boxwoods thrive.
Lynn Batdorf, curator of the national boxwood collection at the National Arboretum in Washington, D.C., notes that there are a total of 97 species of boxwoods worldwide, but only seven of those are suited for temperate climates.
Most boxwoods are tropical growers. There are more than 182 different cultivars of the seven temperate boxwood species.
Boxwoods can often be difficult to please in our area. They prefer an alkaline pH, between 6.8 and 7.5, for optimum growth.
They often suffer from nutritional deficiencies in low pH soil. Most of our native soils in Georgia are acidic, which means that our soils need to be amended to accommodate boxwood culture.
Dolomitic lime is recommended because it contains magnesium, which boxwoods need. It is best to plant boxwoods away from acid-loving plants like camellias, gardenias and azaleas.
Boxwoods have shallow roots that are usually limited to the top 15 inches of soil. The roots often extend out several times the canopy spread.
It is often difficult to transplant older boxwoods because of the amount of root damage inflicted when cutting the rootball.
Fall fertilization is recommended for boxwoods. This promotes root growth and boxwood roots can grow all winter. This can also help prevent winter leaf bronzing, a common boxwood ailment linked to improper nutrition. Magnesium deficiency is usually the cause of tip bronzing.
Proper pruning is vital to healthy boxwoods. They respond best to hand thinning. Sheering creates a thick, dense canopy and prevents light and air flow to the center of the shrub. This often leads to increased twig and leaf diseases. Use hand pruners to make selective pruning cuts.
Boxwood pruning is a gradual process. Georgia Gardener Walter Reeves recommends gradually removing one-quarter of the plant each year, if heavy pruning is required.
This may seem slow, but boxwoods do not respond well to extreme pruning.
For routine pruning, select a few twigs and cut them back to the main stem. This will open up the canopy and allow for increased air circulation.
There are many boxwood cultivars available.
Japanese boxwoods (Buxus microphylla) tend to grow better in Georgia than the more traditional English boxwood (Buxus sempervirens).
There are drawbacks to both. Japanese boxwoods are slow growers and English boxwoods emit an odor similar to cat urine.
Fortunately, there are hybrids of Japanese and English boxwoods, such as "Green Mountain" and "Green Velvet" that seem to incorporate the best of both species.
Clark MacAllister is the Dawson County extension agent. For more information, call (706)265-2442.