Viburnums have long been one of the most popular flowering landscape shrubs, with more than 150 species available, including deciduous, evergreen, and semi-evergreens shrubs. With an almost infinite number of cultivars available, you can find a one to suit any garden—wet or dry, sun or shade, natural or formal, shrub or tree, native or exotic. For most viburnum shrubs, boom times span from early spring through June, followed by attractive fruit and outstanding fall foliage.
Viburnums are well-behaved members of the honeysuckle family. They can be grown as either shrubs or trees, although tree forms may require some pruning to achieve the desired shape. The U.S. National Arboretum has done extensive breeding to create many hardy, pest-resistant varieties.
There is no single type of viburnum foliage. It can be rounded, lance-shaped or toothed, smooth, velvety, or rough. There are some evergreen viburnum varieties, in addition to many deciduous varieties with outstanding fall color. Viburnums work well as hedges or in mass groupings and also make interesting specimen plants or anchors in borders.
Most viburnums have either white or pinkish flowers which are sometimes fragrant. The fragrant varieties are native to Asia. The flowers themselves come in three major types: flat clusters of florets, flat umbels outlined with larger flowers resembling lace-cap hydrangeas, and dome-shaped, snowball-like clusters.
Almost all viburnums produce attractive clusters of fruits that are popular with birds, wildlife, and humans. However, most viburnums are not self-pollinating and will require another variety to cross-pollinate in order to yield fruit.
|Botanical Name||Viburnum spp.|
|Common Name||Viburnum, American cranberry bush, hobblebush|
|Plant Type||Deciduous shrub|
|Mature Size||3 to 20 feet tall, depending on cultivar|
|Sun Exposure||Full sun to partial shade|
|Soil Type||Rich, moist, well-drained soil|
|Soil pH||5.5 to 6.6, but also tolerates slightly alkaline soil|
|Boom Time||Early to late spring, depending on species|
|Flower Color||White, pinkish|
|Hardiness Zone||2 to 9 (USDA), depending on species|
|Native Area||Temperate regions of Northern Hemisphere|
How to Grow Viburnum Shrubs
In general, viburnums are not terribly particular about where they grow, though they prefer fairly rich, moist soil. Viburnums do not transplant well once established, so the best strategy is to plant well-established container-grown plants and take care to choose a location where the shrub will have room to grow. Early spring is the best time for transplanting, giving them a full season to adjust.
After planting, add a 2-inch layer of mulch to keep the soil moist and hold in moisture. During hot weather, the shrubs should be watered every 7 to 10 days. Little pruning is necessary, though some species can be trained to form tree-like plants by removing competing stems.
Viburnums prefer full sun but will tolerate part shade.
These shrubs prefer fairly moist, well-drained soil, but they do not like to have their roots soaking in water. Viburnums like a slightly acidic soil but many types will tolerate alkaline soil.
A deep watering every week is usually sufficient, either through rainfall or irrigation. Native varieties that are well established have a moderately good tolerance for drought.
Temperature and Humidity
Viburnums prefer moderate conditions, though the preferences vary greatly depending on species. Extremely hot weather requires extra watering, and very cold temperatures can stunt the plant or cause dieback.
Most viburnums need little more than one application each year of a balanced, time-release fertilizer mixed into the soil in spring. Once well-established, most shrubs do well without any feeding.
Leggy shoots can be trimmed back in early summer to maintain the shrub's form. Broken, dead, or diseased branches should be removed as soon as you notice them.
Propagating Viburnum Shrubs
Most viburnums sold are hybrids and do not propagate true cannot be started from seed. You can propagate from softwood cuttings during the summer or simply layer branches in the fall. By spring there should be a new plant you can cut off and move.
The fact that few pests bother viburnums is one of the reasons they have become so popular in the landscape. Recently, the viburnum leaf beetle (VLB) has been introduced into North America through Canada and has begun making its way south. The VLB, Pyrrhalta viburni (Paykull), is capable of great damage and is being closely watched. The best way to combat viburnum leaf beetles is to remove egg-infested leaves and to encourage predatory insects. Some organic pesticides are also effective, but avoid synthetic pesticides, which also kill beneficial insects.
Varieties of Viburnum
With more than 150 species available, some of which have dozens of cultivars, choosing a good variety for your region is best accomplished by consulting a local nursery or arboretum. Give the great number of varieties available, it makes some sense to consider in depth some of the best from various categories of viburnum.
Deciduous Asian Viburnums
- Burkwood viburnum (Viburnum x burkwoodii): Suitable for USDA hardiness zones 5 to 8, this variety grows to about 8 feet in height and spread, and is extremely fragrant. Outstanding cultivars include: 'Anne Russell', a compact shrub with pink flowers and red fall foliage; 'Mohawk', an 8- to 10-foot shrub with a spicy fragrance with white snowball flowers that open from red buds.
- Korean spice or Mayflower viburnum (V. carlesii): Suitable for USDA hardiness zones 5 to 7, this plant stays under 6 feet in height and spread. It has pink buds that are very fragrant and open into white snowball flowers. Leaves can be either velvety or rough, like sandpaper. Recommended cultivars include 'Compactum' (slow grower with a maximum height of 3 feet); Vc. x juddii grows to 8 feet and is more open than its parent, V. carlesii.
- Doublefile viburnum (V. plicatum f. tomentosum): Suitable for growing in USDA hardiness zones 4 to 8, this plant grows to a mature height of 10 feet, with a 12-foot spread. It has flowers in flat, double rows, great orangy-red fall foliage, and clusters of red-black fruit. A few varieties are fragrant: V. p. 'Mariesii' and 'Shasta' have the conventional white lace-cap flowers. V. p. 'Kern's Pink' has soft-pink snowball style flowers and purplish edging on the leaves. V. p. ‘Shasta’ grows to 6 feet; it blooms in May with clusters of pure white flowers followed by red fruits. It is suitable for USDA hardiness zones 5 to 8.
- Linden viburnum (V. dilatatum): Suitable for USDA hardiness zones 5 to 8, this viburnum grows to a mature height of 5 feet with an 8-foot spread. It is one of the showiest varieties due to both the flowers and the red fruit clusters. 'Catskill' is a cultivar that grows to only about 5 feet in height and spread.
- David viburnum (V. davidii): Suitable for USDA hardiness zones 7 to 9, this viburnum grows to 3 to 5 feet in height and spread. A native of China, this is one of the most attractive evergreen varieties. It has dark green leaves with dark blue fruit and tiny, tubular white flowers borne on the stem tips. This plant requires both a male and a female plant in order to bear fruit.
- Prague viburnum (V. 'Pragense'): This viburnum is suitable for USDA hardiness zones 6 to 8, and grows to a height and spread of about 10 feet. This rounded, bushy evergreen shrub has glossy, dark green leaves that are deeply veined and contrast with the tubular white flowers that form in domed umbels.
- Leatherleaf viburnum (V. rhytidophyllum): This plant is suitable for USDA hardiness zones 5 to 8, and grows to a height of 15 feet with a 12-foot spread. Native to China, this plant is semi-evergreen in colder climates, losing its leaves when temperatures dip below 10 degrees Fahrenheit. Recommended cultivars includeV. X rhytidophylloides 'Willowwood', which has deeply veined green foliage and flowers in the fall; and V. X rhytidophylloides 'Allegheny', with dark-green leaves that set of the reddish-black fruits. 'Allegheny' flowers in the spring.
North American Shrub-Form Natives
Viburnums native to North America don’t possess the intense, spicy fragrance of their Asian cousins. However, they do offer a fabulous fall display and abundant fruit clusters, popular with birds and wildlife. Most are tough enough for hostile urban environments and many are xeric or drought tolerant. As with all viburnums, they are bothered by few pest problems and possess good disease resistance. The only pruning required is for removing deadwood and to shape or maintain size.
- Arrowwood viburnum (Viburnum dentatum): This species grows in USDA hardiness zones 3 to 8, achieving a mature size of about 10 feet with a similar spread. A native of eastern North America, this plant is very adaptable, growing wild in woodlands, bogs, and along stream banks. It likes full sun to partial shade and is not particular about soil. It can be naturalized and is well-suited to moist areas, but it is fast-growing and will sucker. In spring, it produces white blossoms. The coarsely toothed, pale green foliage changes to yellow, red, or reddish-purple in the fall. The foliage is a larval food for several moth species and the beautiful spring azure butterfly, and the fruit is enjoyed by several species of birds, including bluebirds, cardinals, mockingbirds, and robins. Many birds use the shrubs for nesting and protection. Recommended cultivars include V. dentatum 'Morton', with a rounded, upright habit and deep burgundy fall foliage in fall; V. dentatum 'Blue Muffin', named for its intense blue fruits; V. dentatum ‘Synnestvedt’ Emerald Luster, which has lustrous dark, green foliage.
- Nannyberry (Viburnum lentago): This species grows in USDA hardiness zones 2 to 8 to a mature height of about 12 feet with a 10-foot spread. It prefers moist shade but will weather sun and dry soil. Lace-cap type flowers in creamy white appear in mid- to late-May. The fruits transition from green to yellow to pink and finally deep blue.
- Swamp-haw viburnum (Viburnum nudum): This plant grows in zones 5 to 9, where it achieves a mature height of about 12 feet with a 6-foot spread. It prefers a location with full sun to partial shade. This variety produces white flowers in late June, followed by clusters of round drupes. The shrub is particularly attractive when it has fruits in various transitional colors. The foliage turns reddish-purple in the fall. Recommended varieties include: V. nudum ‘Winterthur,' which has even brighter red coloring and more profuse fruit clusters; and V. nudum ‘Wintertur’, which is self-sterile and needs to be planted with a different cultivar in order to cross-pollinate and produce fruit.
- Hobblebush (Viburnum lantanoides), formerly known as Viburnum alnifolium: This variety grows in USDA hardiness zone 4 to 7, achieving a maximum height of about 8 feet with a spread of 12 feet. A native to northeastern to mid-Atlantic North America, it tends to grow a bit disorderly and is probably best suited for a naturalized setting. Hobblebush is an understory plant that likes moist, shady woodlands. Flat umbels of white flowers appear in May, followed by red fruit clusters that age to the typical blue-black. The leaves are large and fuzzy, and this is one of the earliest viburnums to develop fall colors of reddish gold.
North American Tree-Form Natives
These North American native species that take a tree-like form:
- Maple-leafed viburnum (Viburnum acerifolium): This plant grows in USDA hardiness zones 4 to 8, and achieves a height of 3 to 6 feet with a 4-foot spread. Its canopy is open and casts only dappled shade; it is a good choice for a dry shade location. Flat umbels of creamy white flower appear in late May, followed by almost black fruit. This variety turns an unusual pink in the fall. Maple-leafed viburnum is a larval food source for the spring azure butterfly as well as a nectar source for the golden-banded skipper. Both songbirds and game birds grapple for its fruits.
- American cranberry bush (Viburnum trilobum or Viburnum opulus var. americanum): This plant grows in USDA hardiness zones 3 to 9, where it achieves a mature height of about 15 feet with a spread of 12 feet. It has bright red fruits that look a lot like cranberries and persist well into the winter, making it a favorite of many songbirds and game birds. Although the fruits are not cranberries, they are edible and safe for humans and are sometimes used to make jelly. American cranberry bush makes a good screen or hedge. Its fall color is a rich burgundy. This plant grows wild from New Brunswick through British Columbia and south to New York through Oregon but is not well suited to warmer zones below zone 7. Some recommended cultivars include: V. trilobum 'Phillips',V. trilobum 'Redwing', and V. trilobum 'Compactum Alfredo', which makes a nice low hedge.
- Black-haw viburnum (Viburnum prunifolium): This species grows in USDA hardiness zones 3 to 9. When mature, it is about 12 feet high with an 8-foot spread. Black-haw viburnum does fine in shade or sun and tolerates dry conditions. It doesn’t like salt. It is notable for its pebbled bark, the red stems of its leaves, and the yellow stamens in its white flowers. The dark blue fruits make a nice jelly, but they are usually devoured by birds or wildlife. The fall foliage is red to purple.