Boxwood (Buxus) is a fairly cold-hardy shrub, often used as a hedge. These plants top out at about 20 feet, though most varieties grow to about 6 feet or less. Easily shaped or pruned, boxwood is a slow grower that requires little care, but even if neglected will offer an evergreen element to a home landscape. In general, boxwood should be planted in full sun to part shade in hottest areas, and requires regular water.
The Japanese boxwood (B. japonica) is hardy to -10 degrees Fahrenheit, but looks ragged in the coldest winter climates. A good selection for dry climates, Japanese boxwood thrives in alkaline soil and can tolerate dry heat, though it does require regular water. This plant has round leaves that may be up to 1 inch across and are bright green in summer before turning to brown or bronze in winter. This variety is a popular hedge plant, but if left untrimmed will grow slowly up to 6 feet.
The 'Compacta' cultivar is a dwarf variety with tiny leaves that may be used in rock gardens while the 'Green Beauty' holds its color in colder climates.
The Korean boxwood (B. koreana) is hardy to -20 degrees and is well-known as a good cold-weather shrub that will hold its color where other boxwoods won't. This variety is a slow grower that can reach 3 feet, and may be 6 feet across. The Korean boxwood has bright green leaves that are about 1/2 inch across.
The 'Tide Hill' cultivar is particularly useful in cold climates and will survive even tough New England winters if planted in a sheltered spot.
Common boxwood (B. sempervirens) can grow to 20 feet and, if left untrimmed, may be 20 feet wide. This variety has dense foliage that is bright green and may be up to a few inches across. Common boxwood, which may also be known as American boxwood, will not tolerate alkaline soil and should not be planted in areas that are dry during the summer.
The 'Newport Blue' cultivar has blue-green leaves while the 'Suffruticosa' cultivar is known as English boxwood, and has smaller leaves than others in this variety.