Boxwoods (Buxus species) are highly valued evergreen shrubs recognized for their dense, fine-textured foliage. They provide year-round structure, often used as formal hedges or specimen plants. Successful long-term establishment depends on proper planting technique, particularly the depth of the root system. Incorrect planting depth is a common reason boxwoods fail to thrive, often leading to slow decline and root disease.
Determining the Correct Planting Depth
The primary rule for planting boxwoods is to position the shrub slightly higher than the surrounding soil grade. This is necessary because boxwoods are highly susceptible to root rot, especially in poorly draining soils. Planting high ensures that excess surface water drains away from the base, preventing waterlogging.
The root crown should sit level with or about one-half to one inch above the finished grade. This elevated position accounts for the inevitable settling of the soil after watering. If the root crown is buried, the bark tissue remains constantly moist, which can lead to suffocation and the development of pathogens like Phytophthora.
To locate the proper depth on a container-grown boxwood, remove excess soil until the first main root is visible. This point defines the true top of the root system and should align with the elevated grade. For balled-and-burlapped plants, the top of the root ball dictates the correct height. Planting too shallowly is problematic, as the shallow root system can dry out quickly, causing stress.
Preparing the Planting Site
Preparation of the planting site must be done before the boxwood is placed to guarantee the correct depth and encourage root growth. The planting hole should be excavated to be two to three times wider than the root ball’s diameter. This width is crucial for loosening the surrounding native soil, allowing feeder roots to spread laterally into the landscape.
The depth of the hole should be no deeper than the height of the root ball, or slightly shallower, to support planting high. Digging the hole too deep risks the root ball sinking after backfilling, burying the root crown. Before placing the plant, the base and sides of the hole should be roughened or scored with a shovel to prevent soil compaction and encourage root penetration.
Native soil is recommended for backfilling, but incorporating a moderate amount of organic material like compost can be beneficial in poor soils. This amendment improves soil structure and drainage, but it must be fully mixed with the native soil rather than layered. The focus remains on providing loose soil structure for lateral root expansion.
Immediate Care After Planting
Once the boxwood is positioned at the correct elevated depth, begin the backfilling process using the original or slightly amended soil. As soil is added, lightly firm it with a hand or foot to eliminate large air pockets that can dry out the fine roots. Avoid using excessive force, as this compacts the soil and hinders root growth.
The first watering requires a thorough, deep soaking of the entire root zone. This deep initial irrigation settles the soil around the root ball and removes remaining air pockets, ensuring immediate contact between the roots and the surrounding soil. This initial soaking is far more effective than multiple light sprinklings.
Following watering, apply an organic mulch layer two to three inches deep to regulate soil temperature, retain moisture, and suppress weeds. Keep the mulch pulled back several inches from the root crown and trunk. Creating a donut shape prevents moisture from accumulating directly against the stem, which triggers root crown rot.