Last week I discussed hydrangeas. This week I feel it is only appropriate that I cover viburnums. Many people confuse these two groups of shrubs since they have many similar features.
There are numerous different species of both, but far more species of viburnums exist than hydrangeas. There are over 150 different viburnum species and numerous cultivars of many. From a distance, both often look similar. Upon closer inspection, viburnum buds are basically upright, while hydrangea buds tend to lay down more.
Both have leaves that emerge from stems in groups of two. Hydrangeas and viburnums usually have large flower clusters. The snowball viburnum looks a lot like the snowball hydrangea. Both have large clusters of white flowers.
In general, viburnums have more fragrant flowers, and flowers are almost always white. A few are pink. Korean spicebush and Burkwood viburnum are white and especially fragrant. Most viburnums also usually grow much taller than hydrangeas.
Being taller, viburnums are often less suited for use in foundation plantings. They might be more appropriate for taller buildings though. Their primary landscape use is as accent or specimen plants.
These versatile shrubs can grow in full sun to partial shade. Some types do better in sun, while others like ‘Chindo’, a cultivar with shiny leaves, can tolerate moderate shade. Most viburnums prefer well-drained soils and endure drought very well once established.
Viburnums almost always bloom on the previous season’s wood. This means that viburnums should never be pruned in the fall. Most types bloom in early spring. One should deadhead blooms and prune the plants when flowers start dropping their petals. Otherwise, no pruning is necessary.
As far as hardiness goes, viburnums display a wide range. Many are hardy in northern Canada, while others are adapted to the deep south. Some are deciduous, and other types are evergreen. Still, others are semi-evergreen. This means that in mild winters plants often keep most of their leaves, while in hard winters they lose them.
One nice thing about landscaping with viburnums is that they respond well to renewal pruning, so if plants begin to get too large, they may be cut to the ground much like forsythia can. New shoots will spring up and the training process can begin again.
Most viburnums usually set fruit, which is utilized by wildlife. Highbush cranberries have red fruit that hangs in clusters and resembles cranberries. They are totally unrelated to true cranberries. Other viburnums with red berries are hobblebush and nannyberry. Both have sweet fruit that is delicious fresh and often eaten by wildlife. Fruits make good jelly, too.
Other viburnums can have blue or black fruit. Many of these are edible for humans, but they’re usually sour. Maple leaf and arrowwood viburnums have blue fruits and are highly prized by many different wildlife species. Black haw viburnum is a native black-fruited type that makes beautiful dark jelly.
With a huge array to choose from, viburnums should find their way into almost any landscape. Most are native and that is important to many gardeners, also.
Next year’s flower buds are developing now on this snowball viburnum.
Ted Manzer teaches agriculture at Northeastern High School.
Hi Ted, I hope you and Roberta are well! I had two snowball viburnum in Edenton and brought four rooted off shoots with me when we moved to Raleigh. (1 died) I have terrible soil having to hack my way with a pickax to dig out very heavy (and when dry very hard clay and my viburnum planted on the East side of my yard with little shade struggled and have not grown as well or as fast as they did in my fairly shady Edenton yard. So, I have paid them some close attention and they are doing better. But here’s a question for you. I went to the gardens this spring at the WRAL station. Several acres of lovely plants. They had what I think of as viburnums in bloom that were 12 -18 feet tall. All were labeled hydrangeas. I think they are viburnum since they were tree size and blooming in Spring. So, whose right Ted me or the gardeners at the gardens there.
I’d have to see them and look at the buds. They possibly could have been what they call tree hydrangeas, and they start blooming in mid-spring. If they were blooming in early spring they most likely were viburnums.
It was a really old garden probably there and cared for for fifty plus years.
Oh goodness! From black gum to ‘this’! Although I realize that there are a few species and cultivars of Viburnum that should be more common here, the only one that is common and naturalized is the Viburnum tinus, which I really dislike. I just relocated a bunch, only because they will work nicely as informal hedges. https://tonytomeo.com/2019/09/14/six-on-saturday-recycling-weeds/ . Viburnum davidii is never happy here. I don’t know why. The only viburnum that really does very well, both in bloom and in autumn color, is the Viburnum opulus ‘Roseum’.
I love the fragrance of V. carlesii and V. burkwoodi. They work well as specimen plants but are usually to large for most residential foundation shrub work.
Those names sound familiar. I might have seen them in the Pacific Northwest. I noticed another viburnum with delicate flat topped trusses. I really liked it until I noticed what it was. Viburnums (generally) seem to be happier in harsher climates, such as the Pacific Northwest and Nevada.