Boxwoods (Buxus spp.) are valued for their dense, evergreen foliage and structural permanence, making them a common element in foundation plantings, borders, and formal hedges. Their fine texture and uniform dark green color establish a consistent backdrop in the garden throughout the year. Selecting appropriate companion plants to place behind this defined structure requires careful consideration to introduce seasonal color, varied texture, and contrasting forms. The goal is to soften the boxwood’s formality and enhance its deep color by choosing plants that thrive in similar conditions while providing visual interest.
Matching Environmental Needs
Companion plants must share the boxwood’s preference for certain growing conditions to ensure a healthy, cohesive planting. Boxwoods generally grow best in partial shade, which protects them from intense afternoon sun that can cause leaf scorching. While they tolerate full sun, four to six hours of direct sunlight is often ideal for dense growth, and companion plants should be adaptable to this light range.
Boxwoods require excellent soil drainage, as they are highly susceptible to root rot. Companion plants should also thrive in well-drained, loamy soil with a neutral to slightly alkaline pH (6.5 to 7.5). When planting behind an established hedge, new additions will compete with the boxwood’s shallow root system for water and nutrients.
Aesthetic Contrast and Height Considerations
The boxwood’s tight, small-leaved structure provides a fine, uniform texture that acts as a visual anchor. Plants placed behind them should offer a strong textural contrast, such as those with large, coarse leaves or delicate, airy foliage. Introducing lighter colors—like lime green, silver, or variegated foliage—will make the dark green boxwood stand out and prevent the planting from looking too heavy.
Height is a crucial design element; backdrop plants should be clearly visible above the boxwood without overwhelming it. A guideline is to select plants that mature to a height approximately 1.5 to 2 times that of the boxwood hedge. This ratio allows the companion plants to provide a layered, dimensional backdrop without hiding the boxwood’s structure.
Specific Plant Recommendations
Selecting the right plants involves looking for varieties that meet both the environmental and aesthetic criteria. Plants can be categorized by their growth habit and purpose, ensuring year-round interest and color.
Small Shrubs and Taller Evergreens
These are excellent choices for providing permanent structure and winter interest. Hydrangea varieties, such as H. macrophylla or H. paniculata, offer large flower heads that bloom above the hedge line, providing dramatic contrast in color and form. Upright cultivars of Japanese Maple (Acer palmatum) introduce an airy texture and seasonal color change that complements the boxwood’s solidity. Rhododendrons and Azaleas, if matched to the soil preference, provide a burst of early-season color and a coarser leaf texture.
Perennials and Groundcovers
These introduce softer textures and seasonal flair right at the base of the hedge. Hostas are a choice, offering large, broad leaves in shades of blue, gold, or variegated patterns that contrast sharply with the boxwood’s fine texture. Ferns, such as the Japanese Painted Fern or Autumn Fern, provide a delicate, arching form that softens the boxwood’s rigid lines and thrives in partial shade. Lady’s Mantle (Alchemilla mollis) features soft, ruffled foliage and a light, lime-green color that visually pops against the dark evergreen.
Annuals and Bulbs
These provide flexibility and vibrant seasonal color that can be changed yearly. Spring-flowering bulbs like Tulips or Daffodils can be planted in front of the boxwood, offering a formal display of color before the shrubs fully leaf out. For summer color behind the boxwood, shade-tolerant annuals such as Impatiens or Begonias provide continuous, saturated blooms. These selections allow for an annual refresh of color palettes without disturbing the perennial structure of the planting.
Long-Term Care and Spacing
Proper planting distance is necessary for the long-term health of both the boxwoods and their companions, due to the boxwood’s shallow, fibrous root system. New plants should be positioned far enough away from the boxwood drip line to minimize direct competition for water and nutrients. A spacing of at least 12 to 18 inches from the base is a reliable starting point, increasing with the mature size of the companion plant.
The planting area should be watered deeply and regularly until new plants are established to meet the boxwood’s need for consistent moisture. Applying a two-to-three-inch layer of organic mulch helps retain soil moisture, stabilize soil temperature, and minimize weed growth. The mulch must be kept several inches away from the boxwood’s trunk to prevent moisture buildup and disease.
Pruning is also a consideration, especially for formal shapes. Boxwood hedges should be shaped to be slightly wider at the bottom than at the top. This ensures sunlight reaches the lower branches and maintains foliage density. This practice also benefits companion plants by preventing the boxwood from casting too dense a shadow and competing for light.