Jennifer Schultz Nelson
Extension Educator, Horticulture
In search of a versatile shrub for your landscape? Consider Viburnum, a diverse genus containing over 150 different species, and hundreds of cultivars. Viburnums are native to the northern hemisphere, many native to North America. Ranging in size from small shrubs under three feet tall to small trees about twenty feet tall, there is no shortage in diversity among this genus.
Besides diversity in overall size, diversity in leaves, flowers and fruit are abundant. Leaves vary in size, shape, color and texture. Leaves range from glossy and smooth, to ridged. Leaf shape may be lobed, rounded or lance shaped and entire or toothed around the edges. Many Viburnum cultivars develop outstanding fall foliage color, another great reason to use this plant in your landscape.
Most Viburnum flowers appear in the spring and range in color from pale pink to white. Many are fragrant, adding to their appeal. Flowers may be held in a flat arrangement or a snowball-like arrangement and may be followed by ornamental fruits of red, yellow, blue or near black depending on the cultivar.
Fruits typically appear from late summer to fall, adding to Viburnum's multi-season interest. Viburnums generally do not self pollinate and will produce little or no fruits on their own. I discovered this the hard way after purchasing Viburnum dentatum 'Blue Muffin' specifically to have its blue fruits in my Illini garden. I have had sporadic fruit production at best, nothing like the pictures I'd seen of this cultivar. I've since learned that fruit production is maximized if another Viburnum is grown nearby. What a perfect reason to buy more plants!
Viburnums have lots of great features as far as shrubs are concerned, but what makes Viburnum near perfect in my opinion is they are low maintenance. The Viburnum I currently have in my landscape needs an occasional light pruning but that's it.
Tree and shrub expert Michael Dirr summed up pruning Viburnums by saying, "Pruning viburnums should be an exercise in restraint...again, as with so many things, less is more." Choose the right Viburnum for the right place. If you find your particular choice is growing too large or too leggy for your chosen space, you will be nothing but frustrated with having to prune often to keep the plant in check. This shrub is only low maintenance if you choose a plant with an appropriate growth habit and mature size for the location.
If you have to prune, doing so immediately after flowering will sacrifice some of the fruit, but allow for formation of next spring's flower buds during the summer. If you prune in the late summer or fall, you risk encouraging growth which will be damaged by frost, and will sacrifice spring blooms.
I do occasionally have to prune out a few absolutely vertical, fast growing stems resemble what are commonly called "water sprouts" if they were to grow from the main trunk. What I'm seeing originates a few inches from the base of the shrub, so it is more like a sucker.
Depending on the species and cultivar, it may be possible to train a Viburnum into a single or multi-stemmed tree. Maintaining this shape may require a bit more maintenance over time.
Viburnums tolerate a wide range of soil types and light conditions. Most prefer moderately fertile moist soil, but some will tolerate dry soil. They will tolerate partial sun, but most perform best in full sun.
I know that I need to find at least one more Viburnum to plant in my garden to coax the 'Blue Muffin' cultivar I already have into producing some fruit. I strongly suspect that with such diversity out there among Viburnums, it will be hard to select just one!