Viburnum

Fundamental Facts

HARDINESS: Zones 3 to 10
PREFERRED SOIL pH: Slightly acid
PREFERRED SOIL TYPE: Fertile, well-drained
PREFERRED LIGHT: Sun to partial shade
ATTRIBUTES: Lovely flowers, colorful berries, fall foliage; for beds, hedges, specimens
SEASON OF INTEREST: Spring through late fall; year-round for evergreens
FAVORITES: Choose cultivars matched to your climate and site
QUIRKS: Fruit set is heaviest when multiple plants are grown
GOOD NEIGHBORS: Bluebeard, euonymus, forsythia, juniper, lilac, spirea, summersweet
WHERE IT GROWS BEST: Growing conditions depend on the cultivar
POTENTIAL PROBLEMS: Aphids; fungal leaf spot diseases
PRUNING: Lives far years; prune in spring or after flowering, depending on type
CRITTER RESISTANCE: Good
SOURCE: Nursery plants
DIMENSIONS: 3-20 ft (1-6.1 m) tall and wide

Viburnum in the Landscape

Viburnums are custom-made for carefree landscapes.There are I5O species, and at least that many garden-worthy cultivars, including both evergreen and deciduous plants with a range of sizes, silhouettes, and flower types. Viburnums have it all: attractive foliage in various shapes that turns colors in fall, graceful flowers in white and pink, and prolific yellow, blue, black, or red berries that feed birds in the cold months. It is easy to find one that fits your site and design needs, even if it's difficult to choose from all the plant possibilities.
Viburnums are showy enough to be specimens but also join comfortably with others in a shrub border or foundation planting. In fact, the larger varieties are a beautiful way to soften house corners. Compact plants can be incorporated into flower beds, and evergreens can be massed to create an informal hedge or screen. Note that if you are growing viburnums for their berries, having more than one plant usually improves fruit set.

Sun Lovers for Cold Climates

Hardy to Zone 3. 12 ft (3.7 m) tall cranberry bush viburnums are top choices for sunny sites in cold climates. Both the European cranberry bush (Viburnum opulus) and American cranberry bush (V. trilobum) have flattened, white flower clusters in late spring, maplelike leaves that turn to red in fall, and heavy crops of red berries. These southern range of these species is best limited to Zone 6.

European cranberry bush can attract aphids by late summer. But you can take advantage of the superior aphid tolerance and smaller size of American cranberry bush cultivars. 'Wentworth' grows quickly to 8 ft (2.4 m) tall and wide, has excellent fall foliage color, and bears large, red edible fruits. 'Compactum' grows into a dense 6 ft (1.8 m) tall bush, making it ideal for planting as a hedge. 'Xanthocarpum' has clear yellow fruits that glow in the sun.

Viburnums for Borders and Boundaries

Two sun-loving, fragrant species thrive when grown in moist, fertile soil in Zones 5 to 7. Beginning in spring, the spicy sweet aroma of Korean spice viburnum (V. carlesii) beckons anyone with a sense of smell. Clusters of pink buds open to nearly white, 3 in (7.6 cm) balls of fragrant flowers framed by velvety oval leaves. Unlike most viburnums, this spicy favorite prefers soil with a neutral pH, so you will need to add garden lime according to package directions when planting it in acid soil. At 6 ft (1.8 m) tall and wide, the species is an excellent deciduous viburnum for boundaries or screening, but look for the dwarf, 3 ft (1 m) tall 'Compactum' cultivar when using Korean spice viburnum in foundation groupings.

While not as fragrant as Korean spice viburnum, Burkwood viburnum (V. burkwoodii) is a workhorse among fragrant shrubs and is easier to grow in poorly drained and acid soils. It blooms in spring, with pink buds opening to white, and has glossy, semi-evergreen leaves with felted undersides. 'Mohawk' has dove-scented flowers followed by a good crop of red fruits that ripen to black.

If you're willing to trade spring fragrance for fall and winter color, the linden viburnum (V. dilatatum) is an incredibly trouble-free shrub for Zones 5 to 7. Planted in any sunny, well-drained spot, it will mature into an 8 ft (2.4 m) tall mounded shrub with lovely white spring flowers followed by abundant black berries that persist well into winter. The fall foliage color is usually a strong bronze red, which serves as a beautiful backdrop for the immature berries. Bright red fruit that turns pink following frost is displayed by 'Erie.' 'Michael Dodge' is a cultivar that is literally covered with yellow fruits in fall.

A species grown primarily for its foliage is the leatherleaf viburnum (V. rhytidophyllum). Its oblong evergreen to semi-evergreen leaves reach up to 7 in (17.8 cm) long and are wrinkled above and felted a soft gray on the undersides. Reaching 15 ft (4.6 m) tall, this fast-growing plant blooms with small, fuzzy, flat clusters of cream flowers in late spring and bears plentiful oval fruits that change from red to black. The leatherleaf viburnum looks somewhat like a dense rhododendron, and is perfect for boundary barriers, screens, hedges, and foundation plantings. It is hardy to Zone 5.

Desirable Doublefiles

For gardeners who want spectacular flowers, few shrubs can compete with the doublefile viburnum (Vplicatum f. tomentosum). Mature specimens are at least 10 ft (3 m) tall, and may grow twice as wide, and feature strong horizontal branching. Double rows of showy, bright white, flattened flower clusters appear in late spring along the upper sides of the branches, creating a tiered effect. The bright green, pleated leaves turn reddish purple in fall, contrasting with red berries that turn black. Best in light filtered shade or afternoon shade in Zones 5 to 8, this deciduous viburnum is without peer for stationing at the woodland's edge or near a fence or gate or for balancing the vertical lines of a house.

Cultivars of doublefile viburnum each have their own special charm. 'Mariesii' is the best-known full-sized doublefile, growing 8 ft (2.4 m) tall and wide, while 'Shasta' is popular for its less imposing 6 ft (1.8 m) size. Both 'Roseum' and 'Pink Beauty' have white flowers that age to pink.

Essential Evergreens for Hot Climates

Most viburnums do not perform well in the hottest parts of North America. But there are some wonderful species for Zones 8 to 10 that are usually fragrant, evergreen, and pest resistant. Sweet viburnum (V. odoratissimum) can reach 20 ft (6.1 m) tall and has glossy oval leaves, scented white cones of flowers in summer, and red berries that turn to black. Also fragrant but only 10-12 ft (3-3.7 m) tall, fast-growing Sandankwa viburnum (V. suspensum) is a desirable, drought-tolerant foundation shrub for mild-winter climates. Its white spring blossoms are flushed with rose pink, and the round red fruits turn black.Another good choice is laurustinus (V. tinus), which has glossy leaves, white flowers that open from pink buds, and egg-shaped metallic blue fruits that ripen to black. Hardy to Zone 7, this species makes an attractive informal hedge. All warm-weather viburnums need partial shade to grow well and protection from winter winds when grown in the colder limits of their range.

Growing Viburnum

Viburnums are tough, pest-resistant plants that ask for little beyond a hospitable site that has moist, well-drained soil, usually with a nearly neutral soil pH of 5.0-6.5. Plant out container-grown viburnums in spring, just as they are emerging from dormancy. Prepare planting holes by digging in a 3 in (7.6 cm) thick layer of organic matter, such as compost or leaf mold. Set the plants at the same depth they occupied in their nursery containers, fill the hole around the plants with soil, firm it, and water in well. Top the root zone with a 3 in (7.6 cm) thick organic mulch to keep insect- and disease-carrying mud from splashing onto leaves during heavy rains and to help retain soil moisture. Each spring, apply an organic or timed-release, balanced fertilizer at the rate recommended on the package label.

Extremely hot, humid, or rainy summer weather occasionally causes outbreaks of fungal leaf spot diseases. Don't worry if some of the leaves wither and fall. These resilient plants will recover on their own and be ready to bloom enthusiastically the following spring.

Viburnums need little pruning. Trim them only to remove dead wood or shape the plants. Prune evergreen types in spring and deciduous viburnums right after they flower.