There are several kinds of snowball bush, with types of both Viburnum and Hydrangea laying claim to that evocative name. The Roseum is a popular, easy-to-grow cultivar of the former.
What Is Snowball Bush?
It is important to keep the botanical name of the plant in mind because several different bushes share the common name "snowball bush." Here, we are talking specifically about Viburnum opulus Roseum. The cultivar name derives from the way that the flowers, which start out apple-green and initially morph to white, eventually fade to a rosy color, as do some hydrangea shrubs. An alternate cultivar name is Sterile, which reflects the fact that this produces no berries. Another common name is "snowball viburnum."
This is a fairly large shrub, maturing to 12 feet tall with a similar spread. The leaves are three-lobed and somewhat resemble the leaves of maple trees. Like the latter, they will furnish you with fall color, which is generally a reddish-orange. Botanists classify snowball bush as a deciduous shrub.
Snowball bush is so called because it bears clusters of flowers that are white in color, rounded in shape, and about 3 inches in diameter. Blooming time in a zone 5 landscape is May, so it can be further classified as a shrub that blooms in late spring. It thus offers visual interest in the landscape during two seasons: spring, with its display of flowers, and autumn, with its fall foliage. Another variety that has rounded flower clusters is Viburnum carlesii, the highly fragrant Korean spice viburnum, which has smaller flower clusters.
Where Does This Shrub Grow?
Gardeners in planting zones 3 to 8 can grow snowball bush. The best location for the shrub will be one in full sun (in the North) and with a well-drained, loamy soil (a location in partial shade may be advisable for Southern gardeners).
The species plant, Viburnum opulus (European cranberrybush viburnum) is native to the three continents of the Old World. It bears attractive berries, as does Viburnum trilobum (American cranberrybush viburnum), which is indigenous to North America.
How to Care for Snowball Bushes
Water snowball bush enough to keep its soil evenly moist, as it does not like dry ground. Conserve soil moisture by applying a 3-inch layer of landscape mulch around your shrub, which will have the bonus effect of suppressing weeds. Prune lightly if needed (for example, if you are growing it in a tight spot) just after the flowering period is over.
Fertilize the plant in spring with a slow-release fertilizer or work compost into the earth around the plant at any time. If you find it too costly to buy compost at garden centers, it is easy enough to make your own compost.
Like most plants, you may occasionally have to treat this shrub for disease problems or bug infestations, but preventive measures can be taken. For example, it is a good idea to leave space between your snowball bush and other plants to reduce the chance of attack by bacterial leaf spot or powdery mildew. If you notice aphids on the leaves, spray them with Neem oil, an organic insecticide.
Other Shrubs With This Common Name
People apparently find the name of "snowball bush" appealing, because several other plants have commandeered it as their own common name, including:
- Hydrangea arborescens Annabelle: a classic hydrangea mimicked by the more recent Incrediball hydrangea cultivar
- Viburnum macrocephalum: a very large shrub (it can reach 20 feet tall and wide) with the largest flower heads (up to 8 inches in diameter) among the different snowball bushes
- Viburnum x burkwoodii: a smaller type of viburnum (8 to 10 feet tall) that inherited some of the wonderful smell of its parent, Korean spice viburnum
- Viburnum x carlcephalum: a smaller, vase-shaped hybrid whose parents are V. macrocephalum and V. carlesii, commonly referred to as "fragrant snowball"
Landscaping Uses for Snowball Bushes
Other Viburnum Shrubs:
- Mapleleaf viburnum (V. acerifolium): Seldom used in landscaping, this North-American native should be valued for its tolerance of cold temperatures (to zone 3) and for the unusual color of its fall foliage, which is a deep pink. Its common name refers to its leaf shape. Its size is 4 to 6 feet tall and 3 to 4 feet wide. The yellowish-white flowers (appearing in May) are followed by berries that are at first red, then purplish-black.
- Arrowwood viburnum (V. dentatum) is another valued for its fall color, which is reddish.
- The flowering display of doublefile viburnum (V. plicatum var. tomentosum Mariesii) offers a very different look from that of snowball bush viburnum. The former sports flat-top flower clusters, in contrast to the latter's globular flower heads.