Boxwood shrubs are a popular landscaping choice, valued for their evergreen foliage and versatility. They offer year-round color and structure, making them well-suited for formal hedges, foundation plantings, or stand-alone specimens. Proper spacing is important because it determines the long-term health and aesthetic outcome of the planting. The exact distance between plants depends entirely on the gardener’s objective for the space.
Determining the Planting Goal: Hedge or Individual Shrub
The initial decision that determines spacing is whether the boxwoods will form a continuous hedge or grow as individual shrubs. A hedge is intended to create a solid, uniform green wall, requiring the individual plants to grow into and overlap with one another to achieve a dense effect. This planting style is typically used for formal garden borders, property division, or for edging pathways.
Planting a boxwood as an individual specimen requires a different spacing strategy. The goal is to allow the plant to achieve its full, natural shape, whether that is a globe, pyramid, or rounded form. This approach allows for maximum air circulation around the entire plant, which is beneficial for plant health.
The Spacing Formula: Using Mature Width for Density
The most reliable way to determine the correct planting distance is to calculate spacing based on the mature width of the specific boxwood cultivar. This information is typically found on the plant tag and is a more accurate guide than relying on generic distance recommendations. The mature spread ensures the shrubs eventually fill the desired space.
When aiming for a dense, formal hedge, the spacing between the center of one plant and the center of the next should be approximately one-half to two-thirds of the plant’s mature width. This closer spacing ensures the foliage of adjacent shrubs will touch and interlock within a few seasons, creating a seamless screen. For example, a cultivar like ‘Green Velvet’ with a mature width of 4 feet would ideally be planted with 24 to 32 inches between the centers of the root balls.
Conversely, planting individual specimen shrubs or an informal border requires significantly wider spacing. To allow a boxwood to reach its full, natural size without touching its neighbors, the distance between plant centers should be equal to or slightly greater than the full mature width. A ‘Wintergreen’ boxwood, which can spread to 4 to 5 feet, should be given at least 48 to 60 inches of space. This distance promotes the healthiest growth and best air circulation for a stand-alone plant.
Foundation planting, where boxwoods are placed against a structure, introduces another consideration. The spacing calculation still relies on mature width, but the plants must also be set back from the building to prevent moisture issues and allow future access. It is recommended to position the center of the plant at least half of its mature width away from the foundation, in addition to the distance between the plants themselves. Planting closer than this can lead to restricted air flow and possible structural damage.
Essential Considerations Beyond Spacing
While the distance between plants is a primary concern, the long-term success of boxwoods depends heavily on proper planting technique and site conditions. Boxwoods possess a shallow, fibrous root system that is susceptible to root issues if planted incorrectly. The most common error is planting too deeply, which can lead to crown and root rot, particularly in heavier soils.
Set the root ball so the top of the root flare is slightly above the surrounding soil level. The planting hole should be dug two to three times wider than the root ball but only as deep as the root ball’s height. This ensures the soil will not settle and pull the plant down, and keeps the crown from sitting in pooled water.
Boxwoods require well-draining soil and will not tolerate constantly wet conditions, which can be detrimental to the shallow root system. If the native soil is heavy clay, planting in a raised bed or berm is advisable to improve drainage and prevent standing water. Even when planting for a dense hedge, ensuring adequate air movement through the site is an important factor in preventing fungal diseases such as boxwood blight.