Viburnums Add A Touch Of Class To The Garden

04-24-2000
Viburnums are a rather diverse group of shrubs or small trees that you might want to consider when planning or improving your home grounds. They are a dependable group of plants that have a number of interesting characteristics for all seasons of the year.

Some of the special features of viburnums include fragrant flowers in spring; flower colors of both pink or white; glossy green summer foliage; attractive fall color ; and bright-colored fruit in either late summer or fall. Depending on the species of viburnum selected, it is possible to have a number of these qualities on a single plant during the growing season.

Viburnums are best used as specimen plants where their unique qualities are easily seen or they can be used in a mass border to make an even stronger landscape statement. There are a variety of different sized viburnum so it is important to allow adequate space for the one you choose. If you do provide enough growing room these plants will need only a limited amount of pruning to retain their desirable form and gradually renew the plant.

All viburnums will need well-drained soil that is moderately fertile. A light-textured mulch such as shredded tree bark over the root system will assure an adequate supply of moisture for the plant. If growth is somewhat weak once the plants are established it may be necessary to apply one cupful of a 5-10-5 fertilizer under the spread of the plant. Use slightly less for smaller plants and more for larger material. Over-fertilization however may reduce the number and quality of flowers.

The Korean Spice Viburnum is my favorite because of its fragrant, pink spring flowers on a plant that grows to about 5 feet. The similar Pink Snowball Viburnum is a slightly larger plant with larger, but less fragrant flowers in spring.

The Doublefile and Maries Viburnum have conspicuous, white flowers borne in flat clusters along the upper surface of somewhat horizontal branches.

These plants grow about 8 feet high with an equal spread and produce a red fruit that ripens to black in the fall at about the time the leaves turn a dull crimson.

The evergreen, Leatherleaf Viburnum is hardy only in central and southern Pennsylvania for the most part. Its elongated, glossy green leaves are borne on stems that may reach heights of 15 or more feet, but the plant can be kept pruned to a slightly lower and more compact form. White flowers in the spring contrast well with the foliage and the fruit ripens black.

One of the better tree-form viburnums is Black Haw Viburnum. This is a native that grows 15 or more feet tall with a slightly rounded canopy that can provide a small shade pattern near a patio. The white spring flowers are short-lived, but the deep blue-black fruit will persist up to a month in the fall while the leaves turn a deep purple to red color.

I think one of the best border viburnums would have to be either the European or the American Cranberrybush Viburnum. They develop a thick, dense, upright habit of growth to 10 or 12 feet and fill in quickly to form a screen. In the spring they produce attractive white flowers. During the summer their medium-sized lobed leaves are a deep green before turning a bright crimson in fall. As the common name suggests, the fruit is cranberry-sized, bright red, and edible by both humans and birds. Fruit persists late into fall.

The European Cranberry Bush Viburnum is also available is a more compact or dwarf form that produces quality flowers and fruit at an early age. These can be used to advantage in front of taller types to create a full border from the soil line to the top of the plants in the background.

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**Dr. Robert Nuss is a horticulturist at Penn State. He coordinates all extension horticulture programs. He has bachelor’s, master’s, and doctoral degrees in ornamental horticulture and has been on the Penn State faculty since 1966.