Boxwood vs. Viburnum

Hedge or Screen

• All boxwoods make neat, tight, evergreen hedges or screens, while viburnums make a looser, more open hedge. Only evergreen screens will provide year-long privacy, but many of the deciduous viburnums compensate by providing attractive flowers in spring and colorful berries that often last into winter. Many varieties of the common or American boxwood (Buxus sempervirens) make good formal hedges. The bluish-green "Graham Blandy" (Buxus sempervirens "Graham Blandy") variety reaches 8 feet and grows well in U.S. Department of Agriculture plant hardiness zones 6 through 8. Prague viburnum (Viburnum pragense) is an example of an evergreen viburnum suitable for a hedge. It grows up to 10 or 15 feet high in sun or part shade in USDA zones 5 through 8. Prague viburnum grows rapidly to provide a quick screen and displays 3- to 6-inch fragrant, white flower clusters in spring. American cranberrybush viburnum (Viburnum trilobum) makes a deciduous screen in USDA zones 2 through 7 and also provides attractive flowers, edible red berries and crimson fall foliage.

Topiary

• Although you can use evergreen viburnums to make topiary, boxwoods are the preferred choice. With its compact structure and glossy, small, green leaves, any type of boxwood is suitable for shearing into a formal hedge or topiary. Evergreen viburnums to make topiary are Prague viburnum and leatherleaf viburnum (Viburnum rhytidophyllum). Leatherleaf viburnum prefers part shade and grows well in USDA zones 5 through 7, reaching 10 to 15 feet without pruning or shearing.

Flowers and Fruit

• Although boxwood shrubs, if not pruned too heavily, will flower, the flowers are small and insignificant. In contrast, the flowers and fruit of many viburnums are showstoppers. Burkwood viburnum (Viburnum burkwoodii) covers itself with white, fragrant, snowball-like flowers, which open from pink buds. It grows 6 to 10 feet tall in sun or part shade in USDA zones 4 through 8. Flowers are followed by red to blue-black berries. Another viburnum, cranberrybush viburnum, has attractive flowers and abundant clusters of red berries.

Colorful Fall Foliage

• Boxwoods cannot compete with the colorful fall foliage of many of the deciduous viburnums. American cranberrybush viburnum has striking crimson fall foliage. Doublefile viburnum (Viburnum plicatum tomentosum) has spreading, horizontal branches, creating a layered look. It grows 6 to 10 feet tall in USDA zones 5 through 8 and displays white flowers that look like lace caps. In fall, it makes an attention-getting statement with reddish-purple foliage.

Shade Tolerance

• All boxwoods and viburnums grow well in part shade, but some shrub varieties are better-suited for deep shade. The common or American boxwood variety "Vardar Valley" (Buxus sempervirens "Vardar Valley") is a hardy, highly shade-tolerant boxwood, reaching about 4 feet in USDA zones 5 through 8. Among the viburnums, mapleleaf viburnum (Viburnum acerfolium) thrives in deep shade in USDA zones 4 through 8. Mapleleaf viburnum grows to a height of only 2 to 6 feet and does not mind dry soil.

Deer Resistance

• All boxwoods are highly deer-resistant, and most viburnums are moderately deer-resistant, but Siebold viburnum (Viburnum sieboldii) is highly deer-resistant. This viburnum grows in sun to full shade, bearing attractive flowers and fruit in USDA zones 4 through 8. It is a tall deciduous viburnum, reaching 15 to 20 feet.