Boxwood belongs to the genus Buxus, a family of durable, broad-leaved evergreen shrubs used in temperate landscaping for centuries. Its cultivation dates back to Roman times and possibly as far as 4000 BC. Boxwood’s enduring popularity stems from its consistently dense appearance and ability to maintain a green structure throughout the year. The characteristic compact growth and fine texture of the foliage make it ideal for formal garden design and defining outdoor spaces.
The Defining Features of Boxwood Foliage
The defining feature of a boxwood is its small, simple leaves, which are arranged in opposite pairs along the stems. These leaves are typically oval or elliptical, measuring between a half-inch to one inch long on most varieties. The foliage has a smooth, leathery texture and a glossy upper surface, contributing to the shrub’s neat and polished look.
The color is generally a rich, dark green, though some cultivars present a brighter or yellow-green hue. The underside of the leaf is often a paler green and features a distinct white midvein. Since the boxwood is evergreen, the leaves remain on the plant through the winter, providing continuous color.
Some varieties exposed to harsh winter sun or wind may exhibit a change in color known as bronzing. This temporary shift causes the foliage to take on a soft orange or reddish-brown tint until spring. Boxwood flowers are visually inconspicuous, presenting as tiny, creamy or yellow-green clusters that lack petals. These small blooms appear in the spring and are sometimes fragrant, but they do not contribute significantly to the plant’s ornamental value.
Growth Habit and Common Landscape Forms
Boxwood shrubs are characterized by a naturally dense, multi-branched growth habit that creates a thick, uniform mass of foliage. The plant has a slow growth rate, allowing it to hold a shape for an extended period once pruned. This density and slow growth make the boxwood well-suited for shaping and structural applications in the landscape.
The plant responds well to heavy shearing, which involves cutting the outer foliage to create a defined, smooth surface. This tolerance for pruning makes the boxwood the primary choice for creating formal, architectural shapes. Common landscape forms include precisely clipped hedges that serve as borders, dividers, or green walls.
Its utility extends to creating sculptural forms known as topiary, training the shrub into geometric shapes like spheres, cones, or spirals. Even without formal shearing, the plant naturally tends toward a rounded or boxy silhouette that can be maintained with minimal effort. The fruit is a small, three-lobed capsule that often splits open to release small seeds. These characteristics reinforce the plant’s role as a green architectural element.
Key Differences Among Popular Cultivars
The term “boxwood” encompasses several species and numerous cultivars that exhibit subtle visual differences in leaf and growth habit. Buxus sempervirens, or Common/English boxwood, has a darker green leaf color and can grow into a large shrub or small tree, sometimes reaching 15 to 20 feet if left untrimmed. Cultivars like ‘Suffruticosa’ are dwarf forms of this species, growing densely and slowly, making them ideal for low-growing edging.
In contrast, Buxus microphylla, or Littleleaf boxwood, typically features a brighter, lighter green leaf and maintains a lower, more spreading growth habit, generally staying around four feet tall and wide. The leaves of this type are often more rounded at the tip compared to the slightly more pointed leaves of the English varieties. Other cultivars introduce color variations, such as variegated types displaying white or silvery edges, or those like ‘Blauer Heinz’ which have distinctive blue-green foliage. These differences allow gardeners to select a boxwood that suits the scale and design of their landscape.