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Viburnum

Folkert Siemens Folkert Siemens

Viburnum bears beautiful flowers in the spring, adorns itself with berries in the summer and in turn with vibrant foliage in the fall. How to plant and care for this multi-talent.

General

The plant genus viburnum belongs to the Adoxaceae family and consists of around 150 different species. Virburnums are primarily native to the temperate and sub-tropical climate zones of the northern hemisphere. The wayfarer (Viburnum lantana) and guelder rose (Viburnum opulus) are native to central Europe. There is an entire series of attractive, decorative bushes for the garden among the many viburnum species, these are also winter-hardy in central European climates and bring great pleasure with their flowers and infructescences, as well as their beautiful fall foliage. Nurseries have around 12 to 15 different species and at least as many species and hybrids in their range.

Appearance

Viburnum bushes grow loose or densely branched and often broadly bushy. They can grow up to 16.4 feet tall, depending on the species. The predominantly deciduous leaves are generally positioned opposite one another or in a verticillate arrangement on the branches. They are stemmed and generally form one, although sometimes also three or five lobes with a serrated or smooth leaf margin. The leaves of some varieties turn into attractive fall foliage.

Flowering viburnum

Most viburnum species are covered with flowers in the spring

The spherical or plate shaped inflorescences are composed of several umbels or panicle-like partial inflorescences. They stand on the ends of branches or on short side shoots. The small, fragrant individual flowers have five sepals grown together, and five tubular petals in the lower area that are generally white, or more rarely pink colored and also grown together. In some species and varieties, such as guelden roses, the peripheral flowers of the inflorescences are sterile and somewhat enlarged outwards, such as in the Japanese Snowball (Viburnum plicatum), for example. Each flower has five stamens, the pistil has a stigma in three sections. The flowering period is generally from April to June, however there are some species that open their first flowers as early as November in mild weather conditions and flower right through until March - for example, the arrowwood ‘Dawn’ (Viburnum bodnantense ‘Dawn’) and the Farrer viburnum (Viburnum farreri). Single-seed stone fruit develop from the fertilized flowers; these turn red or blue-black when ripe. The seeds are flattened and sometimes also cordate.

Red viburnum berries

Viburnum berries are red, blue, or black, depending on the variety

The leaves, bark and unripened fruit of the viburnum are poisonous. Consuming the berries can cause vomiting and diarrhea. Ripe berries, however, are not poisonous. It is particularly popular in Russia to take guelden rose harvest after the first frost and turn it into jelly.

Location and Soil

Viburnums are happiest in full sunlight, however most species will also tolerate slight shade. Frost-sensitive evergreen species such as the Laurustinus (Viburnum tinus) and the David viburnum (Viburnum davidii) should be protected from direct sun rays in the winter in particular. Viburnums do well in slightly damp, humus-rich, highly permeable garden soil.

Use

Viburnum bushes can be used in various locations in the garden. There are some species that remain small such as the arrowwood ‘Aurora’ (Viburnum carlesii ‘Aurora’). This barely grows 6.56 feet tall and wide and is therefore also suitable for very small gardens. Whereas the Japanese viburnum grows extremely expansively. It forms horizontal standing branches that are densely covered with white flowers and should therefore definitely be given their own space in the garden to reveal their full splendor. The simple native species work well in nature gardens and are also suitable for mixed flower hedges. The leatherleaf viburnum (Vibunum rhytidophyllum) is evergreen and is popular as a sound screen thanks to its dense foliage. The David viburnum grows wider than it does tall and is excellent groundcover for semi-shady locations. The flowers of the viburnum bush are visited by bees and other insects, however they are not very pollen or nectar rich.

Japanese viburnum (Viburnum plicatum)

The Japanese viburnum (Viburnum plicatum) is characterized by its picturesque, expansive growth

Underplant spring-flowering viburnum species with bulb flowers in coordinating colors. Species with beautiful fall foliage can be readily combined with fall crocuses and various late-flowering shrubs. Group plantings with other fall-colored bushes such as oaks, dogwoods or witch hazel are extremely effective in large gardens. The somewhat frost-sensitive Laurustinus can also be readily cultivated in large plant containers on the patio and is best overwintered in a cool house or well insulated in a sunny, sheltered spot next to the wall of the house.

Planting and Care

In suitable locations, the plants are easy-care and do not require any special attention. After planting and watering the viburnum, spread some horn shavings in the root area and cover the soil with a layer of mulch. Frost-sensitive species will survive the winter better if the crown is wrapped in garden fleece in the fall in sunny locations.

Pruning

Viburnums do tolerate pruning, however they do not require regular pruning as they hardly age at all naturally and flower luxuriantly into old age. If the bushes become very dense, you can remove individual old branches near the soil after flowering. Frozen shoots should be removed in the spring from frost-sensitive evergreen species such as the Laurustinus. Viburnums are also suitable for topiary. When planting and pruning some species, such as the wayfarer and leatherleaf viburnum, sensitive individuals should wear breathing protection: The leaves are covered with fibers that can irritate the eyes and airways.

Arrowwood Viburnum Carlesii

The arrowwood (Viburnum carlesii) is one of the small-growing species

Propagation

The majority of viburnum bushes can be propagated in the early summer with semi-mature cuttings. For this, use an approx. 8 inch long, semi-hardwood shoot. The native wild species can be sown or also propagated with hardwood cuttings. This method also works with some Asian species, provided the soil is evenly damp and humus-rich. Some species, such as the arrowwood, sometimes form offshoots. These can simply be cut off in the fall or spring and replanted in another locations. Grafting is also possible, however it is hardly used anymore today as it is quite labor intensive

Diseases and Pests

The viburnum leaf beetle is particularly bothersome. Its larvae infest the leaves and in the worst case, eat the bush bare. You should check the bush regularly in the spring for signs of an infestation and destroy leaves infested with larvae. The guelder rose is often very heavily infested with aphids in the early summer, but some other species are also susceptible. Powdery mildew is one of the most common diseases. However, it doesn’t generally cause too much damage.

Frequently Asked Questions

When does viburnum flower?

Most viburnum species flower from April to June. Some viburnum species, such as the arrowwood, already flower from November to March in mild weather.

How tall does viburnum grow?

Depending on the species, the bushes grow between 1.64 and 16.4 feet tall.

When can viburnums be planted?

As with most flowering bushes, viburnums are best planted in the spring or fall.

When can viburnums be pruned?

You don’t really need to prune viburnum regularly, however they are extremely tolerant to pruning. The best time for pruning is directly after flowering. If the bush becomes too dense, you can cut off the old branches near the soil.

Are viburnums poisonous?

The leaves, bark and unripe fruit are poisonous. They can cause vomiting and diarrhea if consumed. The fully-ripe berries, on the other hand, are not poisonous and can be turned into jelly, for example.

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