Box hedges are created with the dense, evergreen boxwood plants. Boxwood is thought to be native to Japan, where the plant has been in cultivation since the 15th century. Today there are over 70 different boxwood species with the common boxwood (Buxus sempervirens) and littleleaf boxwood (Buxus microphylla) the most widely used for hedges, screens and borders. Growing a good box hedge starts by providing proper care and spacing the plants correctly.
For creating a smaller-sized formal hedge with boxwoods, space the plants 15 to 20 cm (6 to 8 inches) apart. Plant a little further apart than this if the intended hedge is informal or will be left untrimmed. For creating a thicker hedge, create a double row of box plants and space the rows 90 cm (1 foot) apart. When creating a double row, position each plant in the second row in the centre of two plants in first row or in a zig-zag manner.
Plant boxwoods in the right soil and site for healthy hedges. Boxwoods adapt to areas of full sun that receive some shade during the afternoon. Choose a well-drained ground as boxwoods are highly sensitive to poorly drained, wet soil. The plants prefer a pH of 6.5 to 7. Use 2.5 cm (1 inch) of organic mulch around plants as this reduces erosion, keeps weeds out and retains soil moisture. Recommended materials include pine needles or bark.
Lightly shape the plants after planting and do not wait for the plants to get larger before starting to prune and shape. This helps to keep the hedge well branched all the way to the ground. The rule is to cut back the stems to 15 cm (6 inches) each time they have grown 30 cm (12 inches). Do not allow the top of the hedge to get larger than the base as this will shade the lower portion and lead to weak growth.
The best time to prune boxwoods is during late winter or early spring when the plants are in their dormant state. Do not prune between late summer to early autumn. Pruning at this time encourages the plants to produce fresh, succulent growth that is highly susceptible to cold and frost damage. Avoid lightly shearing the plants continually for long periods. Though this is recommended and keeps the plants in shape, it creates stress on the plant. It is good to also occasionally prune the inner plant areas and thin overall growth.