Grow Guide for Boxwood Plants
Boxwood plants are the quintessential hedge plants. They are evergreen, have small leaves, and tolerate heavy shearing and pruning. Boxwoods have a slow growth rate, have few pests and diseases, and are ignored by deer and rabbits.
Wondering how to grow boxwoods? In this boxwood planting guide, we will learn how to use boxwoods in the landscape to conceal a house’s foundation, for hedges (formal or informal), or simply as small, well behaved specimen shrubs. Boxwoods can be used to create formal hedges between gardens, along paths, and in geometric designs. Growing boxwood evergreens are ideal for informal and mixed hedges, too. Stand alone specimen plants are popular for topiary and even bonsai.
Perfect Plants offers two kinds of boxwoods. The Japanese boxwood (Buxus microphylla var. japonica) can get 5-6 feet high with a similar spread and can be grown in United States department of agriculture plant hardiness zones 5-9. We think these are the best boxwoods for hedges from their uniform height and width. This tall boxwood hedge plant has small, inconspicuous flowers that are creamy white.
Wintergreen boxwood (B. microphylla var. koreana ‘Wintergreen’) is a smaller version that normally doesn’t get more than 2-4 feet tall. Wintergreen boxwood is more cold hardy than the Japanese cultivar, and can be grown in USDA Zones 4-9. Wintergreen is better at keeping its dark green color all winter too, even through the cold weather. The flowers of wintergreen boxwood are yellowish green, but, like the Korean variety, inconspicuous and of little interest. (Wintergreen boxwood is listed by some authorities as B. sinica var. insularis ‘Wintergreen’.
Whichever slow growing boxwood shrub you choose, follow a few simple guidelines and you can expect success.
Planting Site Selection
Boxwoods do best in dappled partial shade where they get full sun for a portion of the day. Too much full sun, especially in hot climates, will damage their leaves.
Used as foundation plantings around the house, boxwoods would be happiest on the north side, and forced to suffer the most direct sun on the south side.
Most boxwood varieties prefer well drained soil where there is no standing water. The shallow root systems do not like wet feet as they are susceptible to root rot if there is not good drainage.
How to Plant Boxwood Hedges
You can plant out containerized boxwoods anytime, but springtime is best time to plant. Avoid planting in winter.
For hedges and foundation plantings, space the smaller Wintergreen boxwoods about 2-3 feet apart and the larger Korean boxwoods 3-4 feet apart. For tall hedges, place them a little farther apart; closer together for lower hedges. Japanese boxwood spacing should be at least 5-6 feet apart. Space the plants with enough room to grow to full maturity. Boxwood hedge spacing is important for keeping the plants to their full size and density.
Dig a hole wider than the pots the plants came in and about the same depth. Carefully remove a plant from its nursery pot and uncoil any roots that may be wound around the root mass. Trim back roots that are unwieldy. Create a little mound in the center of the hole and place the center of the root ball on that, spreading out roots as you backfill the planting hole.
You should leave 2-3 inches of the root mass exposed above the soil line. Water thoroughly while giving the plant a little shaking to eliminate any air pockets.
Spread a 2-4 inch layer of organic mulch over the root zones, but keep it from actually touching the trunks. Water every day or two for the first 2-3 months, until the plants are established. After that, try to get them one inch of water every week or ten days. If the leaves of the boxwood turn yellow, it may be because the roots aren’t getting enough water.
Boxwoods have shallow roots so don’t cultivate the ground close to the root zone and don’t plant other plants too close. Keep your boxwoods mulched.
Three to four weeks after planting, cut the boxwoods back by about a third to a half of their height to encourage bushy branching. Don’t fertilize the first season after planting, but every year after that apply a balanced, all purpose fertilizer such as 10-10-10 early in spring and again in early summer at the top of the root ball. Follow label directions.
Remove dead, misshapen, and crossed boxwood branches, leaves or stems as they appear. Beginning in the second growing season, you should shear your boxwoods two or three times per year with hand pruners or hand shears.
For a formal, box-shaped or contoured hedge or foundation planting, you should prune in early spring and again as necessary throughout the growing season. Don’t wait too long between prunings as this will result in some branches growing too tall and shading out lower green foliage. Each year, cut new growth back by about one-third to one-half until the desired boxwood height of the hedge is reached.
When the shrubs are at the desired height, use a hedge trimmer to create the straight edges or contoured surfaces you desire. For box type hedges, you can use string between wooden stakes to mark where the trimmer should shear. Release your inner artist to control the trimmer for contoured hedges.
Shape the hedge so that it tapers from top to bottom. The hedge should be narrowest at its top, to allow sunlight to reach the bottom. If the hedge is wider at the top, or even the same width as the base, sunlight will be blocked from the lower parts, and leaves will die, leaving unsightly barren branches.
It is important to start good pruning practices early so the maintenance of trimming boxwoods is easier. The longer you wait, the more you will have to prune. Wondering when to prune boxwoods? The best time of year to prune is early spring before the growing season begins.
Boxwood Diseases and Pests
Boxwood blight is a fungal disease that originated in the UK in the 1990’s. It affects leaves and branches of boxwood shrubs with leaf discoloration. Symptoms may or may not be present. Prune back diseased branches and any of the evergreen foliage that has turned. Fungicides may be necessary if the disease gets out of control.
Boxwood Growth Rate
You may be wondering how fast do boxwood grow? Large boxwood plants have a very slow growth rate. Boxwoods grow less than 12 inches per year. Plant this foundational hedge somewhere it can stay put. The shallow root system of these evergreen shrubs make them a great choice for planting under trees.
Maintaining a healthy and attractive hedge takes some effort, but the results can be very satisfying. The perfect shrub for formal gardens!
See also Best Places for Boxwoods for more in depth info on Boxwood planting site options.