Winterthur Viburnum

You really can’t have too many berries in your garden beds for fall color. Why let your garden fade away as the season ends, when you can have it burst into glory instead? There are lots of shrubs that have berries, but for the most striking and unique colors the different viburnum shrubs are a gold mine of pinks, reds, blues and navy-blues. They really spread the spectrum when grown alongside the more common oranges and yellows found in other shrubs. They’re a big group, but don’t think it’s a matter of ‘seen one, seen em all’ – not at all, as ‘diversity’ is their middle name. Plus, many are native to right here in the USA, and with growing our own plants a big gardening trend, you really can’t go wrong. The Winterthur Viburnum is an outstanding example of them, and a great addition to your garden. Not to big and not too small, it’s a upright bush with handsome glossy foliage that reliably turns rich-reds in fall, while the big clusters of berries mix pink and blue together in the same bunch, until winter makes them all turn dark blue, where they hang for months, bringing bitter-sweet beauty to those cold dark days.

Growing the Winterthur Viburnum

Size and Appearance

The Winterthur Viburnum is an upright deciduous shrub, growing 6 to 10 feet tall and around 6 feet wide. It is well-branched from the ground, looking attractive alone or behind other shrubs. The 4-inch oval leaves have a satisfying glossiness, and make an attractive green background in summer. When fall comes knocking they turn bold shades of maroons and purple-reds, deepening and enriching the fall palette of golds and oranges on other shrubs. This plant flowers a little later than most other viburnums, blooming in June or July. The clusters of honey-fragrant blooms can be 5 inches across, and their milky whiteness adds a bright sparkle. They are popular with butterflies and other pollinators, including several valuable native species. If you find the occasional chewed leaf or caterpillar, spare it for the good of our native insects.

By late summer the flowers will have transformed into big, fat clusters of berries that begin white and then change to pale pink. The colder nights of fall turn them darker pink to near-red, until, little by little, they turn dark-blue, so that for a magical few weeks each cluster is a mix of blue and pink berries. Then, with the leaves gone they slowly all turn navy-blue, hanging on through much of the winter. Unlike some other viburnums, these berries are edible, although very acidic. With some sugar, though, they make interesting additions to pies, or they can be turned into satisfying relishes.

For a good crop of berries it is best to plant another variety of this species somewhere not too far away. We recommend the Brandywine™ Viburnum (Viburnum nudum ‘Bulk’) for this. Other good choices are Longwood and Pink Beauty. Both plants will carry big, heavy crops of berries when they pollinate each other.

Using the Winterthur Viburnum in Your Garden

This shrub fits well into more organized, structured garden spaces, as well as into wild and natural settings. Plant it at the back of shrub beds, or in the spaces between windows around your home. Grow it in clusters in larger beds, or even out on a lawn. It also looks great at the edge of woodlands, or in sunny clearings. Grow it as a boundary screen where wilder areas meet the neater garden. For rows and group planting, space bushes 3 or 4 feet apart.

Hardiness

The Winterthur Viburnum is hardy in zone 5 and grows happily all the way through into zone 9, making it available to most gardeners.

Sun Exposure and Soil Conditions

Full sun will certainly give you the richest fall colors and the brightest berry crops, but this shrub will happily grow in areas with a few hours of shade each day. It does do best in damper soils, making it a good choice for low-lying areas, heavy clays, and even boggy spots, but it will be fine in ordinary beds too. It has a slight preference for the acid soils that are normal all through the eastern states, but it isn’t bothered much until the soil becomes strongly alkaline.

Maintenance and Pruning

Beside those occasional chewed leaves we mentioned earlier, the Winterthur Viburnum isn’t much bothered by pests or diseases, so there is nothing to worry about there. It’s also only rarely eaten by deer or rabbits, which is great news for planting in wild areas. It’s very low-maintenance, and best left unpruned and untrimmed. If you do need to do some pruning, do it in late fall, but avoid any summer trimming, or the berry crop will be much-reduced. During long dry spells a deep soak will be greatly appreciated, and keep the berry crop coming along well.

History and Origin of the Winterthur Viburnum

Known variously as possumhaw, wild raisin, or with-rod, Viburnum nudum is found wild across a wide area from southern Canada to Florida, and west into Wisconsin. The berries were eaten by native Americans and used as medicine too. In some areas it is threatened by land-drainage reducing the wet places it thrives in. The variety called ‘Winterthur’ was spotted at the Winterthur Museum and Garden, an estate in Delaware created by the magnate Henry Francis du Pont. It was selected for the exceptional glossiness of its leaves, reliable fall coloring and big berry crop. It was released in the 1980s.

Buying the Winterthur Viburnum at the Tree Center

Just to prove how good it is, in 1991 the Winterthur Viburnum won the coveted Steyer Gold Medal from the Pennsylvania Horticultural Society. A top-rated plant, and one so easy to grow, is always in high demand, so place your order and plan a day for planting, but do it soon, or all our plants will be gone.