The plant genus Snowball (Viburnum) belongs to the family of the muskweed family (Adoxaceae) and consists of more than 150 different species. Snowballs are mainly found in the temperate and subtropical climate zones of the northern hemisphere. In Central Europe, the woolly snowball (Viburnum lantana) and the ordinary snowball (Viburnum opulus) are native. The genus bears its name because of its white and sometimes almost spherical inflorescences. Among the many snowball species there is a whole range of attractive ornamental trees for the garden, which are also hardy in our country and delight us with their flowers and fruit decorations as well as a beautiful autumn colour. The nurseries have about 12 to 15 different species and at least as many varieties and hybrids in their assortment.
Snowball shrubs grow loosely or densely branched and usually broadly bushy. Depending on the species, they can grow to a height of 0.5 to five metres. The predominantly deciduous leaves are usually opposite or whorled on the branches. They are stalked and mostly simple in shape, sometimes with three or five lobes with a toothed or smooth leaf edge. The foliage of some species has an attractive autumn colour.
The inflorescences, either spherical or plate-shaped, are composed of several umbels or panicles. They stand at the branch ends or at short side shoots. The small, fragrant individual flowers have five fused sepals and five tubular, mostly white, rarely pink petals at the base. In some species and varieties, such as the common snowball, the marginal flowers of the inflorescences are sterile and slightly enlarged on the outside, as in the Japanese snowball (Viburnum plicatum). Each flower has five stamens, the stylus has a three-part scar. Flowering time is usually from April to June, but there are also some species that open the first flowers in mild weather from November and flower into March – for example the winter snowball (Viburnum bodnantense ‘Dawn’) and the winter scented snowball (Viburnum farreri). The fertilized flowers produce lonesome stone fruits, which are colored red or blue-black when ripe. The seeds are flattened and sometimes heart-shaped.
The leaves, bark and unripe fruits of snowballs contain toxins. After eating the berries, vomiting and diarrhoea may occur. Mature berries, on the other hand, are non-toxic. They are often harvested from the common snowball, especially in Russia, after the first frost and processed into jelly.
Location and soil
Snowballs prefer to stand in full sun, but most species tolerate light shade. Frost-sensitive evergreen species such as the Mediterranean snowball (Viburnum tinus) and the cushion snowball (Viburnum davidii) should be protected from direct sunlight, especially in winter. A garden soil that is not too dry, rich in humus and well-drained is good for all snowballs.
Snowball bushes can be used in many ways in the garden. There are also some species that remain small, such as the Korean scented snowball (Viburnum carlesii ‘Aurora’). It is barely two metres high and wide and is therefore also suitable for very small gardens. The Japanese snowball, on the other hand, grows very expansively. It forms horizontal branches, densely covered with white flowers, and should therefore be given a single place in the garden where it can develop its full splendour. The simple native species fit well into the natural garden and are also suitable for mixed flower hedges. The snowball with wrinkled leaves (Vibunum rhytidophyllum) is evergreen and is often planted as a noise protection plant due to its thick foliage. The cushion snowball grows more wide than high and is a good ground cover for semi-shade. The flowers of the snowball bushes are visited by bees and other insects, but are not very rich in pollen and nectar.
Spring flowering snowball species should be planted with matching bulb flowers. Species with beautiful autumn colours can be combined well with autumn crocuses and various late flowering perennials. In larger gardens also group-plantings with other herbstfärbenden woody plants like maples, Hartriegel or witch-nuts are very effective. The somewhat frost-sensitive Mediterranean snowball can also be well cultivated in large planters on the terrace and is best wintered in a cold house or well wrapped up in a sun- and wind-protected place on the house wall.
Planting and care
The plants are easy to care for in a suitable location and do not need special attention. After planting and watering, you should spread horn shavings in the root area and cover the soil with a mulch layer. Frost-sensitive species are better able to survive the winter if the crowns are wrapped in a garden fleece at sunny locations in autumn.
Although snowballs are compatible with cutting, they do not need to be cut regularly, as they hardly age naturally and bloom abundantly into old age. If the shrubs become very dense, you can remove individual old branches close to the ground after flowering. In frost-sensitive evergreen species such as the Mediterranean snowball, the frozen shoots are removed in spring. It is also suitable for contour cutting. When planting and cutting some species such as the woolly snowball and the wrinkled snowball, sensitive people should wear respiratory protection: the leaves are covered with fine fibres that can cause itching and irritate the respiratory tract.
Most snowball shrubs can be propagated in early summer by half ripe cuttings. One uses for this about 8 to 15 centimeters long shoots. The local game species can be sown or reproduced by cutting wood. This method also works with some Asian species, as long as the soil is evenly moist and rich in humus. Some species, such as the winter snowball, sometimes form runners. You can simply cut them off in autumn or spring and replant them elsewhere. Although refinement is also possible, it is hardly used any more today due to the high effort involved.
Diseases and pests
The snowball leaf beetle is particularly annoying. Its larvae attack the leaves and, in the worst case, eat the bush bare. In spring the shrubs should be checked regularly for the first signs of infestation and infested leaves should be destroyed with the larvae on them. The common snowball is often attacked very strongly by aphids in early summer, but also some other types are susceptible to it. Powdery mildew is one of the most common diseases. However, as a rule it does not cause much damage.
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.