Shrubs are generally among the easiest plants to care for, and viburnums are easy even among shrubs. This group of large, deciduous, flowering shrubs includes species native to Europe and Asia and others native to the eastern United States. Most flower in spring and have berries and interesting fall color later in the year, so they have multi-season interest in the landscape. As a bonus, the native American species are ideally suited to feeding birds and other wildlife.
Choose a congenial site for your viburnum. Most viburnum species prefer full sun to light shade and will flower and fruit more profusely and have better fall color in a sunnier site. Most viburnums also prefer moist, well-drained soils, though some species can tolerate wet sites and others can tolerate dry ones. Check the specifics for your particular species.
Although not absolutely necessary, your viburnum will appreciate it if you apply a 1-inch layer of compost under the plant each spring. Start 6 inches from the trunk and spread compost out to the drip line (the area under the outermost branches).
Cover the compost with a 2-inch layer of mulch. This will help keep in moisture and keep down weeds. Again, apply the compost starting 6 inches from the trunk and spreading it out to the drip line.
Extra water and fertilizer are generally not needed, particularly for mature and well-established plants. You may water in times of drought (less than 1 inch of rainfall in a week) and during a plant's first year in a particular site, when it is still getting established.
Prune viburnums immediately after flowering. Pruning is not necessary but might be desired to shape the plant. For example, you might wish to shorten taller plants to bring their flowers closer to eye and nose level. You might wish to prune several viburnums into a hedge or a single plant into a small tree by removing all side stems and keeping only the single strongest, central trunk. If mature plants have become very crowded, prune out 1/3 of the oldest stems to thin them.