The versatility of viburnums is legendary!

Viburnum opulus 'Roseum' Picture courtesy F D Richards see his Flickr PageViburnum opulus 'Roseum' Picture courtesy F D Richards see his Flickr PageViburnums are ‘golden-oldies’ that remain popular with gardeners today for their great beauty, hardiness and reliability, and other good qualities like being low-maintenance, problem free, and best of all, long-lived. Read all about growing them correctly below.

Wise gardeners know that the secret behind a really good garden design is to include a selection of hardy shrubs and trees, which form the backbone of the garden, giving it structure and appeal all year round. These structural plants provide interest in the garden with their various shapes and colours, and viburnums fit the bill perfectly!

Viburnum is a genus of about 150 to 175 species of flowering shrubs and small trees in the elderberry or moschatel family, Adoxaceae. It was previously included in the honeysuckle family Caprifoliaceae, and its current classification is based on molecular phylogeny. While most of the plants in the genus are shrubs, some do take the form of small trees, and the name Viburnum comes from the Latin for “wandering tree”. The wandering part of the name likely refers to the plant’s habit of spreading easily as birds consume the fruit.

Viburnums are native to temperate and subtropical Eurasia and North America, with a few species extending into the tropical montane regions of South America and south-east Asia. In Africa the genus is confined to the Atlas Mountains. The cool temperate species are deciduous, while most of the warm temperate species are evergreen.

Most members of Adoxaceae have flat-topped inflorescences composed of numerous small white flowers. The small individual flowers can be 3 to 5mm across with five white, cream or pink petals, and some species are strongly fragrant. The fruit is a spherical, oval, or a somewhat flattened drupe, and can be red to purple, blue or black, and each fruit contains a single seed. Their attractive leaves are opposite, simple, and entire, or toothed or lobed, and are fed on by the larvae of many Lepidoptera butterfly and moth species.

Click here to see Google images of Lepidoptera

Viburnum opulus. Picture courtesy Kazimingi NurseryViburnum opulus. Picture courtesy Kazimingi Nursery(Viburnum opulus) Snowball Bush, Witbalroos, Guelder Rose, European Cranberrybush

This deciduous viburnum is native to the European continent, and is abundant in parts of the northern Nordic countries, but excluding large parts of the Mediterranean in the south. It also inhabits areas of Siberia, The Caucasus, regions of Asia Minor, parts of the countries of Central Asia, and areas of North Africa.

In its native habitat Viburnum opulus grows in and on the edges of forests, and in bushy and riparian areas that interface between land and a river or stream, and around mires, where the soil is often peaty and wet. It is also found growing in moraines, the material left behind by a moving glacier, consisting mainly of soil and rock. Occasionally it is found on the sandy deposits of former glaciers, while it is completely absent from coastal substrates.  In terms of altitude, its natural populations are located almost at sea level up to 1,700m in the Central Alps, and 2,300m in the Caucasus. If it is grown in the right conditions, the snowball bush has a life expectancy of 25 to 50 years.

It is best known as one of the traditional symbols of Ukraine, and is deeply woven into their folklore. Its importance as a symbol dates back to the country’s pagan history when the bright red berries of this viburnum were linked with the immortal fire illuminating heavenly bodies like the sun and the stars. Ritual clothing and the altar cloths used for traditional events were often crafted to include the bright red berries, or the pure white flowers of Viburmum opulus.

In Russian mythology this plant is symbolically linked with passionate love due to the bright red colour of the berries, and the white flowers also symbolise this romantic connection. Due to these strong links with Viburnum opulus, most art and literature from that time mentioning or depicting this beautiful viburnum, originate in Russia or Ukraine.

The red fruits of Viburnum opulus, in addition to their decorative value, are edible and are utilized by many traditional cuisines. However, they are very bitter in taste and not recommended for eating fresh off the shrub. Although Viburnum opulus has garnered great interest from an agricultural and medicinal point of view, and is still used medicinally today, its ornamental beauty did not go un-noticed by plant breeders who saw its potential as a garden plant, and it became the subject of breeding efforts.

Viburnum opulus was planted quite extensively outside of its native range, and in many countries it escaped gardens and naturalized itself where it is was not welcome, and invaded natural vegetation. For this reason plant breeders concentrated on developing sterile plants that do not produce fruits and seeds, but make up for this with the sheer magnificence of their flowers. This led to the creation of several sterile cultivars and varieties that are not invasive.

Click here to see Google images of Viburmum opulus

(Viburnum opulus ‘Roseum’) European Snowball Viburnum 

Roseum is a sterile cultivar that does not bear fruit but remains a firm favourite with gardeners worldwide for its abundance of flowers in spring and early summer. Unlike the wild form, it does not have flat-topped inflorescences, but large, slightly fragrant, hydrangea-like balls of blooms which start out a lovely whitish-green before turning white and then fading to include some rosy pink, hence the Latin name “Roseum”.

In the garden it forms a densely rounded, spreading, upright shrub with arching branches, attaining an average height of t 3 to 4m with a spread of 1.5 to 2.5m, but under favourable conditions it can mature into a large shrub about 8m tall with a spread of up to 4m. This deciduous species has attractive, dark-green, maple-like leaves that turn beautiful reddish-pink and yellow autumn shades, before dropping. Autumn colouring is best in colder regions.

The snowball bush grows in full sun or semi-shade, and although it handles heat very well, in extremely hot regions, some shade would be advantageous. This viburnum is very hardy to frost and cold, tolerating temperatures as low as -18°C.

Click here to see Google images of Viburmum opulus ‘Roseum’

Viburnum tinus. Picture courtesy Wendy Cutler see her Flickr PageViburnum tinus. Picture courtesy Wendy Cutler see her Flickr Page

(Viburnum tinus) Laurustinus 

The evergreen Viburnum tinus is native to the Mediterranean areas of Europe and North Africa, and the Middle East. It is more commonly found in the western Mediterranean due to a shorter drought season and is one of the dominant species of Mediterranean shrub-land, where most of the woody vegetation is called ‘sclerophyllous’, which means 'hard-leaved' in Greek. This type of vegetation generally has small, dark leaves covered with a waxy outer layer to retain moisture in the dry summer months. Viburnum tinus prefers growing in the more luxuriant type of Mediterranean sclerophyllous shrubland, called ‘maquis’ or ‘macchia’ vegetation, that typically consists of densely growing evergreen shrubs. It favours moist, shady areas in the undergrowth of woods, usually near the sea, but it may reach inland to an altitude up to about 800m in the warmest zones of its home range.

The English name, laurustinus, perpetuates early confusion as to its true identity, as it combines the old Latin name ‘tinus’ together with ‘laurus’ as in Laurus nobilis, the Latin name for the Bay Leaf tree, as at that time it was believed that Viburnum tinus and the bay tree were related to one another.

Early records of its cultivation are hard to find, but flaky wall paintings in Pompeii depict this plant. How it spread to places like Britain is also somewhat obscure, but horticulturist and author John Claudius Loudon noted that from 1596 to the end of the century, 46 new plant species were introduced into Britain, including laurustinus. It is certain that the merit of the cultivation of the greater part of them lies with the great gardener and herbalist, John Gerard. By the close of the eighteenth century the different forms cultivated in Britain before 1597 included six cultivars which gained many admirers.

The beautiful evergreen Viburnum tinus has long been prized in cultivation and is very ornamental with its large flattish heads of pink buds which start appearing from mid-winter to mid spring, opening up to display masses of fragrant, star-shaped white flowers that are rich in nectar and will attract bees, butterflies and other pollinators. The blooms give way to clusters of small metallic-blue berries which mature in autumn.

The shrub is bushy, vigorous and fast growing, and young shrubs grow mostly upright, eventually spreading slightly to form a vase shape, with a dense rounded crown of glossy, dark green leaves. Generally it will grow 2 to 3m tall, with an almost equal spread, but mature specimens can reach a height of 5m or more.

Laurustinus grows well in a sheltered position in coastal gardens, and is also very hardy to frost and temperatures as low as −10°C.

Click here to see Google images of Viburmum tinus

Viburnum tinus 'Variegatum' Picture courtesy Leonora (Ellie) Enking See her Flickr PageViburnum tinus 'Variegatum' Picture courtesy Leonora (Ellie) Enking See her Flickr Page(Viburnum tinus 'Variegatum')

Viburnum Tinus ‘Variegatum’, also known as ‘Variegated Laurustinus’, is a compact, spreading evergreen shrub with mid-green leaves that are irregularly margined yellow.  It grows about 1.5 to 2.5m or taller, with an equal spread, and although it is frost hardy it does best in a position that offers protection from cold winter winds. The leaves provide a superb backdrop for the flattened clusters of reddish-pink buds, opening to small, fragrant white flowers that bloom for a long period from mid-winter and into spring, followed by blue-black fruits.

Click here to see Google images of Viburmum tinus ‘Variegatum’

(Viburnum tinus 'Lucidum')

Viburnum tinus 'Lucidum' is a dense, fast growing, evergreen shrub with glossy, leathery leaves that generally grows about 2.5 to 4m in height, with an almost equal spread. Clusters of strongly fragrant, pinkish-white flowers appear in late winter and spring and are followed by showy clusters of bright berries, varying in colour from blue to black, or red. It is an excellent choice for gardeners, both inland and at the coast.

Click here to see Google images of Viburmum tinus ‘Lucidum’

(Viburnum tinus 'Compacta')

Viburnum tinus 'Compacta' remains popular for its ability to be a perfect evergreen specimen for a small garden, a pot, and even a balcony, as it has very compact growth and responds well to clipping in order to keep it even smaller. If grown in the garden it will reach a height of 1.5 to 2m with an equal spread, but with maturity can reach 3m. For a long period in late winter through spring, flattish heads of pink flower buds appear, opening into tiny white flowers. Clusters of small but showy metallic-blue berries mature in autumn. It grows at a medium rate, and under ideal conditions can be expected to live for 40 years or more. It is not particular as to soil type or pH, and is able to handle environmental salt. It is also highly tolerant of urban pollution and will even thrive in inner city environments.

Click here to see Google images of Viburmum tinus ‘Compacta’

Viburnum tinus' Gwenllian' Picture courtesy Leonora (Ellie Enking) See her Flickr PageViburnum tinus' Gwenllian' Picture courtesy Leonora (Ellie Enking) See her Flickr Page(Viburnum tinus ‘Gwenllian’)

Gwenllian is a beautiful evergreen which bears flattened clusters of rosy-pink buds that open into, very fragrant, starry-shaped, creamy-white flowers that are tinged with pink, starting in mid-winter and continuing through spring.  The flowers are followed by metallic blue berries. It’s fully hardy and a popular choice for hedging, growing moderately to 1.5m tall and 1m wide, but can mature to a height of 2.5m. This viburnum is so popular in Britain that The Royal Horticultural Society has given it its prestigious Award of Garden Merit.

Click here to see Google images of Viburmum tinus ‘Gwenllian’

(Viburnum tinus 'Purpureum')

Viburnum tinus 'Purpureum' is a large, fast growing, evergreen shrub which grows 2.5 to 3m tall with an equal spread. It has glossy, dark green leaves with lovely bronzy-purple new growth.  Clusters of small, white flowers, often pink-tinged in bud, are produced over a long period in late winter and spring, followed by blue-black berries.

Click here to see Google images of Viburmum tinus 'Purpureum'

Viburnum sinensis. Picture courtesy Kazimingi NurseryViburnum sinensis. Picture courtesy Kazimingi Nursery(Viburnum sinensis) Sweet Viburnum, Geurviburnum

This is a dense, fast growing evergreen viburnum that can grow to a height of 5m or more, with an almost equal spread. It produces big, shiny, crisp green leaves and small clusters of creamy-white flowers in spring and early summer. There’s a reason why it’s commonly called “Sweet Viburnum” as the flowers produce a strong sweet fragrance. The flowers, and the berries that follow are relatively inconspicuous, and this viburnum is grown mainly for its handsome foliage.

The sweet viburnum will grow in coastal gardens if it is planted a bit inland where it is sheltered from strong salty winds. Although it has been found to tolerate moderate frost and temperatures down to -7°C for short spells, it is less robust than other viburnums, so in extremely cold regions try to site it where it is sheltered from freezing winds, and cover young plants in winter until they are reasonably well established. This viburnum tolerates drought but to look at its best in the garden it requires moderate watering during long, dry spells. In very hot regions it grows best where it receives some shade.

Due to its beautiful foliage, it is a popular choice for a tall, fast growing hedge, informal screening plant, or noise reduction barrier. If pruned regularly, it can be trained into a small shade tree. The roots are not invasive, but it is important to consider the spread of the shrub in small spaces.

Click here to see Google images of Viburmum sinensis

(Viburnum suspensum)

Suspensum is a handsome, evergreen shrub native to Okinawa and other members of the Ryukyu Islands, a chain of Japanese islands northeast of Taiwan. It is fast growing with an attractive, spreading yet compact growth habit, varying in height from 1.8 to 3.5m tall, with an equal spread. It has leathery, dark green leaves, and in late winter to spring it produces a profusion of small, waxy, tubular flowers that are white with pinkish tints.  The flowers are followed by red berries that will darken to black with age.

This Viburnum grows well in warm, moist, humid, frost free regions and takes salty winds. If it is planted in a protected place in the garden it will even tolerate moderate frost.

Click here to see Google images of Viburmum suspensum

Unfortunately, Viburnum suspensum does not seem to be easy to find in South Africa nowadays, but I have left it in my plant index for identification purposes, as it can still be found growing in older gardens and parks, and if you find one you can easily take cuttings.

Members can click here to read more about this viburnum.

Viburnum tinus 'Lucidum' Picture courtesy Kazimingi NurseryViburnum tinus 'Lucidum' Picture courtesy Kazimingi NurseryIn the Garden:

The versatility of viburnums is legendary, as they tolerate a wide range of growing conditions, and there is no limit to the ways in which they can be used in the landscape. They are truly the ‘backbone’ of the garden, adding structure and form, around which the flower garden can flourish.

Viburnums are available as a standard or ‘lollipop’ plants, and grow well in pots or above ground planters in decks etc. making them perfect for gardens both large and small, even balcony gardens.

They can be planted in in full sun, or semi-shade, making them perfect for beds where the sun pattern varies greatly between summer and winter. Although they enjoy quite a lot of sun, they will grow well on the southern side of a house where other sun worshippers would not be so happy. Even in narrow passages between tall buildings, that are usually dark, and often cold wind tunnels where the sun seldom shines, viburnums can grow quite happily. And, the fact that they are virtually pest and disease free is simply a bonus.

Nature lovers will be glad to know that although this shrub is not indigenous to South Africa, its flowers are abundant in nectar and pollen, and it is known for attracting bees, birds and butterflies to the garden. The fruit and seeds are also eaten by birds, and if left unpruned, viburnums will grow tall enough to provide a sheltered habitat for birds.

They look wonderful in the mixed shrub border, and because they respond well to pruning, and can be clipped into any shape, viburnums are used for topiary, or for formal or informal hedges and screens. In a larger garden, you could plant several in a crescent, circle, or square to create a ‘garden room’ where you will be able to relax in privacy. Vast farm gardens can accommodate rows and rows of them as formal or informal hedges, to act as windbreaks that will protect other plants.

On the patio or next to the pool, planted in large pots or above ground planters, they become dramatic foliage plants, and can even be trimmed into balls or cubes to ensure they are never in the way of those using the deck or pool. In the herb or vegetable garden, you can trim them regularly to form low hedges that help keep dogs and other animals out.

Like other woody shrubs, the flowers or stems of berries cut from Viburnums can last for weeks in a vase if the water is changed regularly. Adding a few drops of bleach or vinegar to the water will help keep it fresh for longer. A sprinkle of sugar in the water can keep also keep the flowers perked up for longer, but it can also trigger bacteria growth, so be sure to change the water often if you add sugar or any other mixtures to maintain cut flowers over longer periods.

Bearing in mind all of the above, and that living hedges and screens are great for screening noise, reducing air pollution, and providing wind protection, why not treat yourself to a couple of these reliable, low-maintenance shrubs, they are long-lived, low-maintenance, and truly beautiful!

Viburnum opulus Fruit. Image by Irmeli Koskenoja from PixabayViburnum opulus Fruit. Image by Irmeli Koskenoja from PixabayCultivation:

Viburnums grow well in most regions of South Africa but thrive in the cooler, temperate regions. Almost all viburnums are pretty tough and cope well in very cold Highveld gardens. Very heavy frost can damage the leaves of some varieties, but they grow out again quite quickly. In very hot and dry inland regions they will require regular watering in summer, and will benefit from some shade during the hottest time of the day.

In South Africa viburnums are known to grow in the cooler parts of our subtropical regions, but are not recommended for very humid subtropical regions. However, in places like South Florida USA, both Viburnum odoratissimum and Viburnum suspensum are widely grown, and if you take a ride down any street you're likely to see them, so I don’t see why these two viburnums shouldn’t do well in our humid, subtropical regions too. In humid regions they would do well in open spaces where they are correctly spaced and there is a good airflow, and drip irrigation would be perfect to discourage leaf diseases like powdery mildew.

Unfortunately, Viburnum suspensum is not easy to find anymore, but I have left it in my plant index for identification purposes, as it can still be found growing in older gardens and parks and is easily propagated. Click here to read more about this viburnum. 

Even the wet winters of the Western Cape don’t pose a problem, and viburnums actually do quite well in winter rainfall regions, as long as they can be watered in summer. Viburnums will grow well fairly close to the sea and can take quite strong winds, but remember, in the wild many coastal types grow in protected woods and will struggle if totally exposed to the sea.

Full sun is best, but light shade such as that cast by buildings and other large shrubs and trees is not a problem. Viburnums even grow well on the shady southern side of the house where other sun-loving shrubs will not be so happy. However, in shade that is too deep the foliage will become sparse and the plants will not flower.

Viburnums prefers light, sandy, and even chalky soil, but will adapt to most garden soils, growing well in loamy soils, and even heavy clay, as long as it does not remain waterlogged. Like everything, they will do better if you treat them kindly, so give them a good start by adding compost and a dressing of superphosphate or bone meal to the planting holes.

Remember to give them enough room to develop, and, as with all woody plants, plant high, exposing as much of the taper at the base of the trunk as possible, as allowing soil or mulch to accumulate round the base of a tree can be fatal. Newly planted shrubs will need regular watering until they are established.

In times of crisis, established viburnums can survive a short period of drought, but in order to look at their best in the garden, water moderately but regularly throughout summer, and sparingly in winter.

A spring application of mulch, together with a balanced fertiliser, is usually sufficient to keep them looking at their best, but you can also feed in midsummer, using an organic 3:1:5 fertiliser or equivalent. If the leaves appear a little pale, a little extra feeding with a fertiliser that is high in nitrogen will be beneficial. This is particularly good for the plants if they have recently been pruned drastically. Only use LAN fertiliser if you can give the plants extra water for a few weeks, otherwise this quick-acting fertiliser may burn the roots and foliage.

If necessary, viburnums can be pruned for neatness throughout the year, making them great for hedges or screening, for topiary, to create standards, sturdy ‘lollipops’ and other shapes. If left unpruned, they will develop a beautiful shape on their own, perhaps only requiring a light trimming occasionally. Because of their large leaves, prune using secateurs, not shears.  

Older plants that have outgrown their space can be ‘reinvented’ by removing all the lower branches, retaining only one or two of the larger main stems and the upper branches attached to them. These branches are then trimmed regularly, so that the foliage becomes denser. This will create a cute little tree in whose shade you can plant some new perennials.

Propagation:

Viburnums can be propagated either by soft or hardwood cuttings. Softwood cuttings taken in late spring tend to root much easier than hardwood cuttings taken in autumn or winter.

Softwood cuttings should always be taken with sharp, sterilised instruments. The best size is a 10 to 15cm section taken from vigorous shoots. Take specimens in the morning, preferably after rain. Remove the leaves from the lower third of the cutting. Provide a rooting medium of 1 part peat and 1 part perlite, or substitute horticultural sand for the perlite, if preferred. Pre-moisten the rooting medium before planting.

Rooting hormones will enhance rooting but are not strictly necessary. Remember, using too much rooting powder is not a good thing, and you only need a touch on the cut end of the stem. Insert the cutting into the prepared medium down to one-third, or half its length. Cover the trays or pots with plastic and place them in indirect light. Keep the medium lightly moist, and mist the cuttings occasionally with water. Rooting times are variable, and cuttings can be checked about 4 weeks later by gently tugging on one to see if it is rooted.

Hardwood cuttings can be a bit more difficult and a rooting hormone is definitely recommended. Take an angled cutting about 20 to 25cm long, with several growth nodes. Remove all leaves on the cutting and dip the cut end into water, then into a small amount of rooting hormone. You may use the same medium you use for softwood cuttings or a mixture of 40 percent peat moss and 60 percent perlite. Cuttings can be planted into containers at two-thirds their length and then treated the same as softwood cuttings. The cuttings will survive through winter with light watering or misting, and roots will emerge quickly in spring.

Problems, Pests & Diseases:

Healthy viburnums are not bothered by any serious pests or diseases, but can be susceptible to aphids, bacterial leaf spot, stem blight, and powdery mildew.

Warning:

Some viburnum fruits are edible for humans, but many others are mildly poisonous. Other parts of the plant like the leaves are mildly toxic if ingested, so it is always wise to supervise small children in the garden, and to discourage pets from chewing on plants.