Boxwoods (Buxus spp.) are evergreen shrubs valued for their dense foliage and ability to hold shape in formal garden designs. Relocating established plants is challenging due to the physiological stress placed on the root system. This guide provides an approach to successfully transplanting boxwoods. Following specific techniques minimizes plant stress and promotes rapid establishment in the new location.
Optimal Timing and Pre-Move Preparation
The most favorable time for relocating boxwoods is when the shrub is dormant, typically in late fall after the ground has cooled or in early spring before new growth buds swell. Transplanting during dormancy significantly reduces the water demand on the foliage. This helps mitigate desiccation stress on the compromised root system. Moving a boxwood during summer or the active growth phase places undue strain on the plant’s ability to recover.
Before excavation, a light reduction of the canopy is beneficial to minimize the leaf surface area demanding water from the transplanted root system. Selective thinning of interior branches also allows for better air circulation and light penetration. This pruning should maintain the natural shape of the boxwood while reducing the volume of foliage.
For larger, established boxwoods, preparing the root system six to twelve months in advance is an effective strategy. This preparation involves root pruning, which stimulates the growth of a dense, fibrous root ball closer to the trunk. Root pruning increases the volume of functional roots retained when the plant is moved, significantly improving its chances of survival.
To execute root pruning, use a sharp spade to cut a circle into the soil around the boxwood, defining the perimeter of the future root ball. The spade should cut straight down, severing the lateral roots and creating a distinct trench. This action forces the plant to allocate energy into forming a compact root system inside the defined area. Maintaining consistent soil moisture ensures that new feeder roots develop robustly before the move.
Excavating and Replanting the Boxwood
The size of the root ball is the most important factor in a successful transplant, determined by the boxwood’s trunk diameter, or caliper. A guideline suggests calculating a root ball diameter of 10 to 12 inches for every inch of trunk caliper, measured 6 inches above the soil line. Ensuring the root ball is adequate maximizes the retention of fine, water-absorbing feeder roots.
Begin excavation by digging a trench just outside the planned root ball circumference. Use a sharp, straight-edged spade to cut cleanly and vertically down. This straight-sided approach maximizes the volume of functional root mass retained and prevents the root ball from becoming cone-shaped. Once the sides are cut, carefully undercut the ball to sever any deep taproots.
After the root ball is freed, immediately wrap it in burlap, canvas, or heavy plastic sheeting to keep it intact and moist during the move. Securing the fabric tightly prevents crumbling, which causes extensive root damage and increases the risk of transplant shock. Keeping the root ball completely intact is paramount for the boxwood’s survival.
The receiving hole should be significantly wider than the root ball, ideally two to three times its width, but it must be no deeper. Digging a wide hole loosens the surrounding soil, allowing new roots to easily extend outward into the native environment. The bottom of the hole should be firm enough to support the root ball without allowing the plant to settle deeper over time.
Position the boxwood so the top of the root ball is level with, or slightly above, the surrounding grade. Planting too deeply is a common error that can lead to stem rot and decline of the shrub. The original soil line visible on the trunk should serve as the precise indicator for the final planting height.
Backfill the hole using the native soil removed during excavation. Avoid amending the soil with excessive organic matter near the root ball. Amending the soil can create a distinct boundary that discourages roots from venturing into the surrounding native soil. Gently firm the soil around the base to eliminate large air pockets, but do not compact the earth excessively, which restricts oxygen flow to the roots.
Post-Transplant Establishment and Care
Immediately after backfilling, thoroughly soak the root ball and surrounding soil to settle the earth and ensure maximum root-to-soil contact. This initial deep irrigation is a necessary step to remove any remaining large air pockets that can cause roots to dry out. A soil berm created around the perimeter of the hole can help contain the water during this initial soaking.
The first year following the move is the establishment period and requires careful, consistent deep watering. Instead of frequent, shallow sprinklings, water deeply when the top few inches of soil begin to dry out to encourage roots to grow downward. Checking the soil moisture by hand or with a probe prevents both desiccation and waterlogging, which are common causes of transplant failure.
Apply a 2 to 3-inch layer of organic mulch, such as shredded bark or wood chips, across the entire root zone. Mulch helps regulate soil temperature, reduces surface water evaporation, and suppresses competing weeds. Keep the mulch several inches away from the trunk flare to prevent moisture accumulation that could foster disease.
Boxwoods may exhibit signs of transplant shock, such as defoliation or browning of the leaves, as they adjust to the new location. Providing temporary protection from intense afternoon sun or harsh winter winds can reduce stress during the first six to twelve months. This protection allows the plant to focus its limited energy reserves on root regeneration rather than mitigating environmental stress.
Avoid applying high-nitrogen fertilizers during the first year, as the plant needs to focus energy on root regeneration rather than top growth. Fertilizing transplanted shrubs can stimulate shoot growth prematurely, placing an unsustainable demand on a root system that is not yet functional. Once the boxwood shows clear signs of successful establishment, typically in the second growing season, a balanced slow-release fertilizer can be applied.