Buxus microphylla ‘Wintergreen’ is a popular, cold-hardy evergreen shrub valued for its dense, compact foliage that retains its deep green color throughout the winter. Proper planting distance is a fundamental decision that dictates the plant’s ultimate form, whether it is a continuous, solid green barrier or an individual, rounded specimen. Correctly calculating the spacing is also important for the long-term health of the plant, ensuring adequate air circulation to prevent common fungal issues. The correct measurement depends entirely on the gardener’s goal for the landscape design.
Understanding Growth Habits and Mature Size
The ‘Wintergreen’ Boxwood typically develops a mounding, broad shape, reaching three to four feet in height and four to five feet in width. The mature width is the most important measurement for determining planting distance, as it dictates the space the shrub will occupy. Since the growth rate is relatively slow, crowding plants together will not produce an instant hedge but will lead to long-term problems.
When boxwoods are planted too closely, the dense foliage restricts air movement, creating a humid microclimate. This lack of air circulation is a major factor in the development and spread of fungal diseases, such as boxwood blight (Calonectria pseudonaviculata). Conversely, spacing shrubs too far apart results in visible gaps that may take many years to fill in, defeating the purpose of a continuous border. Planting decisions must balance the desire for quick, dense fill with the necessity of maintaining plant health.
Spacing for Dense Hedges and Borders
To create a formal, solid green hedge, the goal is for shrubs to grow together quickly, forming a seamless wall of foliage. The planting distance should be calculated as one-half to two-thirds of the plant’s mature width, measured center-to-center. Given the ‘Wintergreen’ Boxwood’s four to five-foot spread, the recommended planting distance is 24 to 30 inches.
Planting at 24 inches ensures the outer edges of mature plants overlap by 12 to 18 inches, guaranteeing a solid, integrated appearance. This tighter spacing encourages branches to intertwine and grow upward, creating the dense texture of a formal hedge. Because the plants are closer, a more aggressive pruning schedule is required early on to shape the sides and encourage dense branching. Maintaining a slightly tapered hedge shape, wider at the bottom, is necessary to ensure sunlight reaches the lower branches and prevent dieback.
If a less formal, but still continuous, border is desired, spacing can be increased to 30 to 36 inches center-to-center. This wider spacing takes longer to fill in but allows the plants to eventually touch and merge. The increased distance also marginally improves air circulation between young plants, which is advantageous in humid climates.
Spacing for Individual Specimen Shrubs
When the goal is to showcase the ‘Wintergreen’ Boxwood’s natural, mounding form, it should be planted as an individual specimen shrub. This requires spacing the plant far enough from neighbors and structures to allow it to achieve its full, unconstrained mature size without competition. For a plant with a four to five-foot spread, the planting distance should be equal to or slightly greater than the maximum expected width.
A spacing of five to eight feet apart, measured center-to-center, is recommended for specimen planting. This provides a clear zone of three to four feet around the mature plant, ensuring its natural, rounded habit is fully visible. Maximizing the distance increases light exposure and air flow, which naturally reduces the risk of fungal pathogens. This spacing also minimizes the need for heavy, corrective pruning, allowing for a more natural growth habit.
Preparing the Site for Accurate Planting
Implementing the calculated spacing measurements requires careful site preparation to ensure correct alignment and depth. Once center-to-center distances are determined, use a string line or spray paint to clearly mark the exact location of each planting spot. This visual guide is important for maintaining a straight row, especially for formal hedges where precision is necessary.
The planting hole should be dug only as deep as the root ball, but two to three times as wide to allow the shallow, fibrous roots to spread quickly. Before backfilling, place the root ball so the top edge of the root flare is slightly above the surrounding grade, typically by about an inch. Planting the boxwood too deep is a common mistake that leads to suffocated roots and poor plant health.