Boxwood: An Historic Shrub
Boxwood: An Historic
Shrub for Williamsburg Gardens
By Shirley Livingston, Master Gardener Volunteer
Many James City County residents, influenced by historic gardens in this area, have boxwood plantings in their gardens. Although boxwood is considered to be a low-maintenance shrub, it is subject to a number of diseases that can be minimized by knowing your plant and its growing requirements.
Boxwood was introduced to North America from Europe in the mid-1600s and soon became a popular plant in formal gardens and hedges. Although there are approximately 160 varieties, three are commonly seen in our local gardens. Buxus sempervirens, the common or American boxwood, can attain a mature height of 15 to 20 feet. The wood and roots are highly prized for carving. Highly prized for its wood, it is used as a foundation, corner or screening plant.
The cultivar, buxus sempervirens suffruticosa or “English” boxwood is very dwarf and slow-growing. The leaves are quite fragrant. It is used for edging and can be pruned regularly to maintain its dwarf shape. However 150-year old plants can attain a height of 3 feet. Finally, there is buxus microphylla (Japanese or Korean boxwood). Japanese boxwood rarely grows more than 3 feet tall and is usually used as an edging or low hedge plant. Japanese boxwood tends to suffer fewer disease problems than common or English boxwood.
As if it were not confusing enough for “American” boxwood to have originated elsewhere, there are also boxwood impersonators. The dwarf yaupon holly is distinguished from boxwood by its leaves. Smooth boxwood leaves sit directly opposite one another on the stem, while the scalloped holly leaves are arranged alternately.
The most important factor in preventing disease is to plant boxwood properly. Boxwoods should only be planted in well-drained soils. They grow best in semi-shade, although they will live in full sun. Once established, deep water boxwood during periods of drought. Boxwood can be pruned or sheared in spring for shaping or to remove any branches killed by winter cold. A soil sample analysis submitted to Extension will provide specific fertilizer recommendations for your particular site. A sign of nitrogen deficiency is the yellowing of leaves, particularly older leaves inside the plant.
Some of the diseases and pests to which boxwood is subject are Phytophthora root rot, English boxwood decline, nematodes, volutella stem blight, leafminer, mites, and psyllid. If you suspect you have any of these problems, you can obtain further information from the following links:
Major Diseases of Boxwood, by Mary Ann Hansen, Virginia Tech
You can also take samples to the Extension office for analysis.
Don’t be overwhelmed by the list of possible problems. Boxwood can provide a delightful addition to your landscape – it’s even deer resistant!
Further details on boxwood culture and history may be obtained from Selecting Landscape Plants; Boxwoods, by Alex X. Niemiera, Associate Professor, Horticulture, Virginia Tech.