This hybrid Buxus is typically grown in evenly moist, well-drained loams (e.g., sand-clay mixture) in full sun to part shade. Plants will grow well in a variety of part shade situations, including open sun-dappled conditions or light shade with several hours of morning sun or early afternoon sun. Plants can grow in close to full shade, but typically are less vigorous and more open with decreased foliage density. When grown in full sun, plant foliage is more likely to scorch, bronze in winter or suffer from mite attacks. Plants prefer soils with a pH of slightly acidic to slightly alkaline. Plants are generally tolerant of pruning and shearing. Pruning should never be done prior to the last spring frost date. Pruning too early in spring often promotes tender new growth that may be damaged or killed by a late spring frost. Avoid cultivating around plants because they have shallow roots. Roots appreciate a good organic (e.g., bark or compost) mulch (1-2”). Thin plants and remove dead/damaged branches annually to improve air circulation. Boxwood is best sited in locations sheltered from strong winds, with, if possible, some protection from full winter sun. Foliage may bronze in winter when exposed to half day to full day sun. Winter winds can remove moisture from leaves at a rapid rate, often resulting in dehydration and bronzing. Carefully remove heavy snow accumulations as quickly as practicable to minimize stem/branch damage.
'Green Mountain' is a dense, upright, evergreen boxwood that typically grows to 2-3' tall over the first 10 years. This is a slow-growing hybrid shrub that may eventually mature to as much as 5-7' tall. It was introduced by Sheridan Nurseries of Oakville, Ontario, Canada in the mid-1960s as part of the Sheridan Series. Parents are thought to be B. sempervirens 'Suffruticosa' (female) and B. sinica var. insularis (male). Smooth-margined, narrow-elliptic leaves (to 3/4" long) are glossy dark green. Foliage may acquire bronze tones in winter. Small, somewhat inconspicuous, apetulous, greenish-cream flowers in terminal and axillary clusters bloom in April and May. Genus name comes from an old Latin name. Common name of boxwood is in reference to the prior use of the wood to make boxes. Another theory on common name is that the name is in reference to young plant stems which are quadrangular (square box cross section).
Boxwood can be somewhat temperamental to grow in the St. Louis area where its evergreen foliage tends to bronze (turn unattractive brownish-yellow) in harsh winters, particularly if plants are located in open areas exposed to full sun and winter winds. Otherwise, boxwood requires little special care other than annual pruning. No serious insect or disease problems. Some susceptibility to blights and leaf spot. Root rot can also be a problem in poorly-drained soils. The three main insect pests of boxwoods are boxwood leafminer, boxwood mite and boxwood psyllid. In the deep South, nematodes are of concern. New growth is particularly susceptible to winter damage.
Specimen/accent, hedge, mass. Foundations. Formal gardens.