Boxwood shrubs are the classic choice for creating formal, dense hedges, providing year-round structure and evergreen color. Their fine-textured foliage and tolerance for close shearing make them versatile plants for defining borders, paths, or garden rooms. A successful boxwood hedge requires thoughtful planning and proper planting techniques that support the plant’s naturally shallow root system. This guide details how to establish a thriving, continuous hedge.
Selecting the Site and Preparing the Soil
Boxwood requires a location that balances sun exposure with protection from harsh elements. While the shrubs tolerate full sun, partial sun (four to six hours daily) or afternoon shade is preferred, especially in warmer climates, to prevent leaf scorch and winter bronzing. Protection from strong, drying winter winds is also important, as these can severely dehydrate the foliage.
Boxwood health depends on well-drained soil, as the plants will not tolerate constant wetness around their roots. Before planting, conduct a soil test to determine the existing pH level. Boxwood thrives in soil that is near neutral to slightly alkaline, ideally between pH 6.5 and 7.5. If the soil is too acidic, incorporate amendments like dolomitic lime to raise the pH.
To prepare the planting bed, incorporate organic matter, such as compost, into the native soil. This improves drainage in heavy clay soils and enhances water retention in sandy soils. Spacing is determined by the mature width of the chosen variety. For a dense, continuous hedge, space plants at half to two-thirds of their expected mature width, typically resulting in centers between 12 and 24 inches apart.
Step-by-Step Planting Technique
Begin planting by digging a continuous trench along the hedge line, or individual holes. The trench or hole should be two to three times wider than the root ball, but only as deep as the root ball itself. Boxwoods have shallow root systems, and planting them too deep can lead to suffocation and decline.
Remove the boxwood from its pot and inspect the root ball for circling roots. Gently slice or “score” the outer layer of roots in several places to encourage lateral growth into the soil. Set the plant so the top of the root ball is level with, or slightly above, the surrounding soil surface. Planting slightly high accounts for settling and prevents the crown from sitting in water.
Backfill the space around the root ball with the amended native soil, tamping gently to collapse air pockets. Avoid heavy compaction, which impedes root growth and water penetration. Finish with a thorough, deep watering to settle the soil around the newly planted roots.
Initial Care for Hedge Establishment
Immediate, deep watering is the most important step for survival and reducing transplant shock. Saturate the entire root zone, repeating this deep watering regularly during the critical first 18 months, especially throughout hot summers. The shrubs generally need about one inch of water per week, either from rainfall or supplemental irrigation.
Monitor soil moisture consistently, allowing the top layer to dry slightly between waterings to prevent root rot. Apply a two to three-inch layer of organic mulch, such as shredded bark or compost, over the planting area. Mulch conserves moisture, moderates soil temperature, and protects the shallow root system. Crucially, keep the mulch several inches away from the plant’s crown to maintain air circulation and prevent disease.
Shaping and Maintaining the Hedge
The long-term success and aesthetic of the hedge depend on proper, timely pruning to encourage density. Pruning should begin in the second season after planting, once the plants have established a strong root system. The primary goal is to create a form that is wider at the bottom and narrower at the top. This shape allows sunlight to penetrate the lower foliage, preventing the bottom branches from becoming bare.
For a dense, formal appearance, shearing the outer layer of growth is common. This should be complemented by “pick pruning” or “thinning.” Thinning involves selectively cutting back longer interior branches with hand pruners to allow light and air into the hedge’s interior. This internal light exposure maintains foliage density throughout the entire shrub.
Pruning is best performed in late spring or early summer after the initial flush of new growth has hardened off. Avoid heavy pruning in late summer or fall, as tender new growth will not harden before the first frost and will be susceptible to winter damage. Apply a light application of a balanced, slow-release fertilizer in early spring to support continuous health and vigor.