The Viburnum Bush
Viburnums are a medium-sized group of bushes, some evergreen and some deciduous. They grow all around the northern parts of the world, from America through Europe to China, and they are grown for their flowers, colorful berries, fall foliage, and often for all three. They vary from a foot or two in height up to small trees, but most are bushes between 6 and 12 feet tall. A diverse group, they are easy-to-grow garden shrubs, often able to grow in shade and wet soil, and great plants for filling beds and for planting in semi-wild areas. Some are highly-prized for their scented winter or early spring blooms, and all of them are interesting plants that help make your garden a more diverse and charming place to be in.
Using Viburnums on your property
Where you choose to grow Viburnums in your garden will depend a lot on which ones you are choosing. They are mostly used in shrub beds, but they can also be planted in natural areas, and some are useful in planter boxes too.
Larger Viburnums can be planted in shrub beds, mixed with other flowering shrubs. Most of them are hardy, so they are especially useful in cooler zones, where shrub choices can be limited. Larger types are great in the background, where there green leaves and white or pink blossoms fill out your garden picture and make a great setting for smaller shrubs. Some can be used in the middle ground, between tall shrubs and smaller edging plants, and there more colorful or scented ones will be good choices.
Most Viburnums are excellent plants for growing in natural areas. Some are American native plants, so they are perfect choices for natural gardening, but even non-native species look completely at home along the edges of woods, or beside streams. Many grow well in wetter soils, so waterside planting is an obvious choice, and they are perfect for those often-difficult low-lying places.
Many Viburnums are naturally bushy, making them great for screening. Some, especially evergreen types, can be clipped, but they are usually best when allowed to grow naturally, allowing flowers and berries to add lots of interest. When you need to fill empty corners of your yard, they can be planted in groups, and their bulk and calming greens really give substance and solidity to your garden planting. Every plant in your garden shouldn’t be a prima donna, and the plants of the chorus line are just as important. Of course, so Viburnums deserve a place in the front row!
What is a Viburnum Like?
Most Viburnum bushes are rounded and upright, with some just a foot or two tall, and others reaching 12 feet or even more. The branches are usually thick and stiff, with a bark that can be pale beige or dark brown. The bark is often marked with many small bumps, called lenticels, which allow air into the stems.
The leaves are arranged in pairs along the stems, and they are usually simple ovals, with a pointed tip. Some have serrated edges, and others have the leave partially divided into several lobes. Some have pronounced veins, and they may be glossy or roughly textured. Bright fall colors of rich reds and oranges are often seen.
The individual flowers of Viburnums are small, but they are carried in clusters, often making large flower heads. Sometimes these heads of flowers are dense and tight, and other times they are flat, and more open. Flowers are usually white, but some are pink, and buds can be white, pink or red.
After flowering most varieties produce clusters of berries, which will usually be red, purple, blue or black. These often make an attractive garden show, and some are edible, and those are excellent used in the kitchen for pies or preserves. They are always popular with birds, and can be a valuable winter food for them.
Hardiness and Growing Conditions
By choosing suitable types, you can grow Viburnums from zone 2 to zone 9. Most grow easily in zones 5 to 8, with plenty of choices for hotter and cooler zones too. Evergreen varieties grow best in warmer zones, as the leaves can be damaged by cold.
Many of the Viburnums will tolerate shade, making them very useful, as most gardens have shady areas beneath trees. This is often the natural habitat of Viburnums, so they are ideal choices. Most will also grow well in full sun, making them very versatile.
Almost all Viburnums will grow well in average garden conditions, and few of them have special needs. Quite a few grow well in wet soils, which makes them valuable if you have low-lying and damp areas. A few tolerate drought well, and some tolerate salt-spray too.
Planting and Initial Care
Prepare the planting spot by digging in some organic material and removing roots of weeds. The night before planting you should soak the pots thoroughly, and when planting take a sharp knife and cut down the length of the root ball in a couple of spots, from top to bottom to cut through circling roots. These can restrict root development, while cutting them will encourage the roots to spread out and develop vigorously. Water once or twice a week for a few weeks after planting, and then less often. Varieties that grow well in wet soil may not be very drought tolerant, so watering during hot, dry weather is beneficial.
Caring for Viburnums
Once planted and established most Viburnums take care of themselves, and they don’t need much attention at all. This makes them ideal for low-maintenance and natural plantings.
Some spring pruning can be helpful with some types, to encourage vigorous growth. Remove any weak stems, and trim back long branches to a pair of buds, to keep plants denser and more compact. In colder zones it is natural for the ends of the branches of some Viburnums to die back. Simply remove the dead tips for neatness, back to the first healthy buds. On older, vigorous plants, removing some of the oldest stems at the ground will encourage new growth. Wait until after blooming to prune spring flowering varieties.
Pests and Diseases
Most Viburnums are free of serious pests or diseases, so control is almost never needed. In cold, northern zones there have been occasional outbreaks of the Viburnum leaf-beetle, Pyrrhalta viburni, although this pest, which came from Europe, is mostly found only in Canada. It can cause extensive leaf-loss, and it is best controlled by careful removal of the stems that contain the egg masses during the winter. It usually only attacks European species of Viburnum.
Some Popular Garden Viburnums
With over 150 species, only the most interesting find their way into our gardens. We can divide them into three broad groups, depending on where they come from originally. The emphasis in garden plants is on attractive blooms, scented blooms, berries and exceptional fall color.
American Cranberry Bush (Viburnum trilobum) – this bush is widely grown, and it is hardy from zone 3 to zone 7. It has lobed leaves that look a little like maple leaves, and flat heads of white flowers in spring. The red berries make an attractive show before being taken by birds, and they are excellent in the kitchen, for tarts and preserves. It has rich burgundy fall colors. The variety ‘Redwing’ has exceptional fall color and red-tinted spring growth, while ‘Compactum Alfredo’ is a dwarf form that is useful for low hedges.
Possum-haw (Viburnum nudum) – also called wild raisin and withe-rod (used for divining water), this is a beautiful shrub for natural gardens. Wild plants can be 12 feet tall, but there are several selected forms that are more compact. They also show strong fall colors and heavy berry crops. Perhaps the best is Brandywine™ (‘Bulk’) which has rich scarlet and burgundy leaves in fall and berries in clusters of both pink and blue at the same time.
Nannyberry (Viburnum lentago) – this is a very hardy plant, growing even in zone 2. It forms a bush up to 12 feet tall and 10 feet wide, and thrives in damp shade, a location that few other plants enjoy. The white flowers are followed by berries that pass through green, yellow and pink before ripening black.
Black-haw (Viburnum prunifolium) – an upright shrub to 12 feet tall and 8 feet wide, this is a plant that will do well in sunny, drier places, unlike most of the others. It also grows in shade. The fruit is dark blue and makes good jelly. The fall colors are dark red and purple. Hardy everywhere from zone 3 to 9.
Arrowwood (Viburnum dentatum) – a great shrub for natural gardening, the fall leaves are rich, deep red, and the berries are blue to black. Very popular with native birds for both food and nesting sites. Hardy from zone 3 to 8, it grows well in most soils and situations, including damp soil and shade.
European Cranberry Bush (Viburnum opulus) – almost identical in appearance to the American Cranberry Bush, the red berries are edible in small quantities, but very inferior to the American plant. Also called Guelder-rose, it can grow into a broad shrub ideal for background planting, reaching 12 feet tall and wide. It is hardy from zones 4 to 8. Two cultivated forms are useful: ‘Nanum’ is a dwarf shrub just 2 feet tall by 3 feet wide. The variety ‘Roseum’ is an old form that is always popular, with showy flowers like small white hydrangeas, but it doesn’t produce berries.
Wayfaring Tree (Viburnum lantana) – also with white flowers, this tree has simple oval leaves with prominent veins, and berries that turn red at first, and later black.
The emphasis in these bushes is on the perfumed flowers, sometimes pink, which are in tight, rounded heads and open with the first warm days of spring. Because the flowers buds are formed before winter, they are not as hardy as many other viburnums.
Korean Spice Bush (Viburnum carlesii) – the pink buds open white in this shrub, and they are richly fragrant. It grows about 6 feet tall and wide, with roughly textured leaves. It grows in zones 5, 6 and 7. The similar hybrid called Viburnum x juddii grows to 8 feet, with a more open form.
Burkwood’s viburnum (Viburnum x burkwoodii) – this bush can reach 8 feet, with very fragrant flowers. The variety ‘Mohawk’ is a US Arboretum introduction, with red flower buds and it grows from zone 5 to zone 8.
Dawn Viburnum (Viburnum × bodnantense ‘Dawn’) – this hybrid between two Chinese species was created in 1935, and it is outstanding for flowering anytime from fall to spring, during warm spells. The pale pink flowers are very fragrant, opening from deep pink-red buds. It can grow to 10 feet tall, in zones 7 and 8.
Doublefile viburnum (Viburnum plicatum f. tomentosum) – this startingly beautiful shrub has broad horizontal branches that are covered in spring with large white flower heads that make it look like snow-covered branches. Fall colors are oranges to reds. It will grow from zone 4 to 8, although after a harsh winter in zone 4 it may fail to bloom. Some varieties have rounded, hydrangea-like flower heads.
Laurustinus (Viburnum tinus) – coming from around the Mediterranean and the Canary Islands, the rounded glossy leaves of this shrub look great all year, growing in zones 8 and 9. The rounded flower heads are pink in bud and then white, opening in late winter, with some fragrance. It grows well in damp shade.
Leatherleaf (Viburnum rhytidophyllum) – fully evergreen in zones 8 and 9, this Chinese shrub loses it leaves in winter, but is perfectly hardy, all the way into zone 5. It grows as much as 15 feet tall and 10 feet wide, so it is perfect for filling larger spaces. The large leaves (8 inches long) have a heavy, wrinkled texture and a dark color. The variety ‘Willowood’ flowers in fall, but others flower in spring, with blue berries turning black in fall.
Prague Viburnum (Viburnum rhytidophyllum x utile) – this hybrid plant, a cross betweenthe leatherleaf viburnum and the service viburnum, was created in 1955 by a gardener at the Prague Municipal Nursery, Czechoslovakia. It is the only evergreen viburnum that will stay green in cold climates, and it is completely hardy in zone 5. It is also happy in hot summers and it grows well in zone 8. It has attractive dark-green leaves, pink flower buds, and red berries that ripen to black. An excellent evergreen for colder zones.
With so much diversity, there are Viburnums for every garden, in every zone. They should form part of the basic planting when establishing a garden – just choose the ones that are best for where you live, your garden style and your climate.