Flowering Shrubs for the Landscape and the Birds
Viburnums have long been one of the most popular flowering landscape shrubs. There are over 150 species of Viburnum. You can find a variety to suit any garden need: wet or dry, sun or shade, natural or formal, shrub or tree, native or exotic, USDA Zones 2-9. Bloom times span early spring through June and are followed by attractive fruit and outstanding fall foliage.
Viburnums are well behaved members of the honeysuckle family. They are either shrubs or trees. The tree forms may require some pruning to achieve the desired shape. The U.S. National Arboretum has done extensive breeding for hardy, pest resistant varieties.
Viburnums work great as hedges or in mass groupings and also make interesting specimen plants or anchors in borders.
Most viburnums prefer full sun but will adjust to partial shade. They like a moderately fertile soil with a pH between 5.6 - 6.6., although many do just fine in alkaline soils. In general, viburnums are not terribly particular about where they grow.
That few pests will 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 trough Canada and has begun making its way south.
There is no singular viburnum foliage. It can be rounded, lance-shape or toothed, smooth, velvety or rough. There are some evergreen and semi-evergreen varieties and many deciduous varieties with outstanding fall color.
Almost all viburnums produce attractive clusters of drupes type fruits which are popular with birds, wildlife and humans. However, most viburnums are not self-pollinating and will require another variety to cross-pollinate with and yield fruit. Read more on Asian and Evergreen Viburnums and Native North American varieties.
The Oregonian Viburnum trilobum 'Wentworth' Edible viburnums, also known as highbush cranberries, are worth a closer look for their beauty and their value as edible berries. Although no relation to real cranberries (Vaccinium macrocarpon), these viburnums taste similar, produce more berries and are easier to grow than cranberries. Viburnum lantana, or the Wayfairing Tree, produces berries that are edible, but mostly used as famine food. They are not succulent.
Generally, viburnum berries are not known to be toxic, although they don't necessarily taste very good.
Guelder-rose (Viburnum opulus) was introduced as a cultivated ornamental and can grow across southern Canada. Occasionally, the shrub may become naturalized. The fears of serious poisoning reported in older literature seem unfounded. Humans who ingest the berries may experience mild symptoms.
Most viburnums have either white or pinkish flowers which are sometimes fragrant. The flowers themselves come in three major types: 1) Flat clusters of florets, 2) Flat umbels outlined with larger flowers, resembling lacecap hydrangeas and 3) Dome-shaped, snowball like clusters.
The fragrant varieties that are most familiar in the landscape are native to Asia.
The Morton Arboretum has this to say about VLB:
Viburnum leaf beetle feeds only on viburnums. Viburnum leaf beetle has been known in some eastern states since the early 1990’s. A few possible sightings of this pest were reported in 2013 and 2014, and in 2015, the beetle was reported across the Chicago region with some regularity. This insect feeds as both larvae and adults and can do extensive damage. If left unchecked it can lead to the death of the shrub, in as little as two or three years. Some species of viburnum are more susceptible to the beetle than others.
Highly susceptible species of viburnum are the first to be attacked, and are generally destroyed in the first two to three years following infestation. Common viburnums that are considered highly susceptible include: Viburnum dentatum (arrowwood viburnum), V. nudum, (possum-haw, smooth witherod viburnum), V. opulus (European cranberry-bush viburnum), and V. opulus var. americana, formerly V. trilobum (American cranberry-bush viburnum).
If you want a good viburnum resource in your personal library, consider purchasing Viburnums: Flowering Shrubs for Every Season by Michael Dirr.
You can contact us at viburnumsrule@viburnums.com