Boxwoods (Buxus spp.) are popular evergreen shrubs known for their dense, fine-textured foliage. They are frequently used to create formal hedges, define garden spaces, and provide year-round structure. While boxwoods are relatively low-maintenance once established, planting distance is the most important factor for their long-term health and achieving the desired appearance. Correct spacing determines whether they will form a solid green wall or maintain their individual, sculpted forms.
Understanding Mature Size and Growth Habit
The correct planting distance depends entirely on the specific cultivar you choose and its ultimate mature size, not the size of the small shrub purchased at the nursery. Boxwoods vary dramatically; a dwarf variety like ‘Morris Midget’ may only reach two feet wide, while some American Boxwoods can spread over eight feet across. Always research the cultivar’s mature width and height before planting a single shrub.
Planting based on current size is a common mistake that leads to overcrowding as the plants mature. Insufficient spacing prevents proper air circulation between the dense foliage, which is a significant health concern for boxwoods. Poor airflow creates a humid microclimate, an ideal environment for the fungus Calonectria pseudonaviculata, which causes Boxwood Blight. Correct spacing is a preventative measure against this and other fungal diseases.
Calculating Spacing for Dense Hedges
When the goal is to create a continuous, impenetrable hedge or border, plants must be spaced close enough so their branches merge to form a single green mass. The specific formula for a dense hedge is to space the plants at a distance equal to approximately one-half to two-thirds of the variety’s mature width. This ensures the plants intentionally grow together within a reasonable timeframe, creating the desired tight, formal appearance.
For example, if you select a ‘Winter Gem’ boxwood that matures to a spread of four feet, you would space the center of each plant two to two-and-a-half feet apart. This close proximity forces the plants to grow into each other, eliminating gaps and establishing a solid, uniform hedge. For the fastest and densest screen formation, you can employ a staggered planting pattern, sometimes referred to as a triangular pattern, where the second row of plants is offset from the first.
Spacing for Standalone Plants and Foundation Use
When the intent is for each boxwood to stand as an individual specimen or foundation planting, the spacing rule shifts completely to prioritize light and air circulation. In these applications, the plants should be spaced far enough apart to allow them to reach their full mature width without their branches touching. This approach ensures the plant maintains its natural, individual shape and maximizes its long-term health.
A good guideline for standalone use is to space the plants at a distance equal to their full mature width, or even slightly more, measuring from the center of one plant to the center of the next. For a boxwood with a six-foot mature spread, you would plant them six to seven feet apart on center, which is significantly more space than the three to four feet needed for a hedge. This wider spacing allows sunlight to reach all sides of the shrub, prevents the dense, moist conditions that encourage Boxwood Blight, and keeps the lower foliage from becoming sparse. Proper spacing for individual plants maintains the integrity of each shrub’s form, whether it is a tidy globe or a conical shape.