What you should know about boxwoods shrubs

Boxwood is a widely grown evergreen that deserves its popularity. You can find them in many large commercial gardens but they also work nicely in small residential yards. This is some important information on these ornamental darlings.

• Dwarf forms can be used to anchor flower beds or edge walkways, while larger types fit well into foundation plantings.
• Boxwoods make an excellent backdrop for bulbs or perennials with light foliage and add a background for sitting areas or entryways.
• Be careful when digging around boxwood roots. Injured roots are entry points for soil-borne, fungal root-rot diseases
• Typically slow-growing, boxwood will endure for centuries. Its only limitation is poor tolerance of extreme cold.
• While there are cultivars suited to every area, common boxwood (Buxus sempervirens) is usually hardy to Zone 6, while littleleaf boxwood (B. microphylla) is hardy to Zone 5 and tolerates summer heat better.

• Prepare planting holes by working in a 10-centimetre-deep (four-inch-deep) layer of compost or other organic matter, as well as sharp sand if the site catches runoff water.
• Set out plants in either spring or fall and expect to see little new growth the first year. Boxwoods often do not reach full size for five to eight years.
• Boxwoods have a naturally neat look, but you can prune them if you prefer a tight shape.
• Avoid pruning in late summer. The resulting growth is easily injured by freezing weather.

Most cultivars offer good disease resistance, but boxwood can have problems with scale, tiny immobile aphid relatives. They hide on leaf undersides and suck plant juices, causing leaves to turn pale.  Control by spraying with dormant oil in late winter. When entire plants or major sections turn brown, the problem is likely root rot. Remove plants promptly and replace with a moisture-tolerant species.

Cultivars of common boxwood offer many variations in size and shape. Here are some of the most common:

• Myrtifolia -- grown since the 1700s, is a one metre (three foot) shrub with narrow leaves.
• Handworthensis -- grown since the 1870s, it is dark green and strongly upright.
• Graham Blandy -- a column reaching 3.5 metres (11.5 feet) tall.
• Vardar Valley -- a relative newcomer from the 1950s. It takes cold in stride and forms a mounding shape to 60 centimetres (25 inches) high and one metre (three feet) wide.
• Suffruticosa -- also called edging box. It is another old variety that seldom grows taller than 60 centimetres (25 inches), making it good for a low hedge.
• Littleleaf  -- is generally smaller in leaf and stature than common boxwood.
• Green Pillow -- has a spreading habit, reaching only 40 centimetres (15 inches) tall but one metre (three feet) wide.
• Curly Locks -- is an upright grower, to 60 centimetres (25 inches), with slightly twisted branches.
•  Korean boxwood (B. m. var. koreana) -- is a very slow-growing variety. It tolerates both heat and cold well but may still brown in winter.
• Green Mountain and Green Gem -- Remain green all winter and reach 60 centimetres (25 inches) to one metre (three feet) tall and wide.

This evergreen's small leaves makes it attractive for hedges and entranceways. The many varieties mean you can find one that will suit your climate and space.