In late spring, other viburnums start to take over. The guelder rose, V. opulus ‘Roseum’, sometimes called the snowball tree, is a large shrub up to 4 metres tall grown for its sprays of showy pompom flowers during May and June – excellent for cutting. Smaller but similar in flower is V. plicatum ‘Popcorn’, which is smothered in spherical, white blooms in spring, while V. plicatum ‘Pink Sensation’ has pale pink powder-puff flowers. Confusingly, V. plicatum var. tomentosum and its cultivars have completely different flowers, more like lace-cap hydrangeas with flat heads of lacy fertile flowers surrounded by larger sterile bracts. The cultivar ‘Mariesii’ is one of the most dramatic, with distinctive horizontal layers of flat-headed flowers against dark-green leaves. Growing to about 3 metres, it can be grown as a stand-alone specimen or even trained against a wall or fence.
One of the most useful viburnums to grow for a double season of interest is V. nudum, which has white flowers in May, followed by attractive berries in autumn. But to get a good crop of berries you must plant two cultivars of the same species so they can cross-pollinate. Shrub specialist Karan Junker suggests planting ‘Winterthur’ and ‘Pink Beauty’ together, either near each other or even intertwined in the same planting hole. Both cultivars have lovely berries that morph through an interesting colour spectrum as they mature, from greeny white to pink then bluish-black, often with different colours in one cluster – all displayed against tinted autumn foliage. The flowers are an attractive creamy white but are subtle rather than show, held in delicate umbels over the foliage. Other berried viburnums include the native wayfaring tree, V. lantana, which has clusters of crimson berries turning black, and V tinus, with its dark metallic-blue-black berries. V. lantana ‘Aureum’ is an unusual form with golden leaves that can lighten up a dark corner of the garden, and indeed is best in light shade as the golden foliage can be scorched by hot sun.
How to grow, prune and care for viburnum
Most viburnums are easy to grow and will flower obligingly with very little prompting. The only thing they dislike is being waterlogged, so well-drained soil is essential. Most species are best left to their own devices, when they will form a natural, multi-stemmed shape, needing little or no pruning apart from the occasional removal of dead or damaged branches. However, V. tinus responds well to clipping, and can even be cloud pruned to form an undulating hedge that will grow well in shade. Grow larger flowering species such as V. plicatum var. tomentosum and V. × bodnantense in long grass as stand-alone specimens; smaller varieties such as V. carlesi and V. x burkwoodi can be integrated into a border, perhaps under-planted with pale-pink or mauve tulips that will pick up the colour of the flowers.
When buying viburnums, bear in mind their provenance. Plants from commercial garden centres may be grafted specimens with a vigorous rootstock, resulting in weaker specimens that produce lots of irritating suckers. It’s best, therefore, to choose plants from specialist nurseries, which grow their own stock from cuttings. More expensive they may be, but you will end up with a stronger, shapelier and healthier shrub.
Where to buy viburnum
A good range of viburnums is available from shrub specialist Junker’s Nursery in Somerset (01823-400075; www.junker.co.uk)
