Snowball viburnum, also known as snowball bush, is a deciduous, multistemmed shrub named for its huge snowball-like flower clusters. It is frequently confused with the sun-loving Pee-Gee hydrangea, though fortunately they bloom at different times -- the true snowball bush in spring, Pee-Gee in late summer or fall. The ideal time to plant snowball bush depends on where you live, but you can plant container-grown shrubs spring through fall.
A very old-fashioned shrub common in European gardens at least since the 1500s, snowball bush was grown throughout the original 13 Colonies. The sterile European species (Viburnum opulus "Roseum") produces large snowballs at the end of 12-foot arched stems in late spring. The fertile form of this plant is known as the European cranberry bush, with flower clusters that produce bright-red berries. Chinese snowball bush (Viburnum macrocephalum "Sterile") is even more dramatic, sometimes growing to 20 feet and producing snowballs up to 8 inches across. Japanese snowball bush (Viburnum plicatum plicatum) is smaller -- but still plenty large, at 15 feet -- and grows more loosely and produces smaller blooms.
Stems of snowball bush make excellent cut flowers, very dramatic in spring arrangements. Even after blooming, snowball bush is still an attractive specimen shrub or small tree, if you're willing to prune and train it. Place it at the back of a large bed or border to build layers of visual interest. Snowball bush works well as a privacy screen. In warmer locales where it's almost evergreen, plant multiple shrubs to create a hedge or property boundary. Dwarf versions of the snowball bush such as Compactum, which grows to just 6 feet, and 2- to 3-foot Nanum are more suitable for small yards.
When to Plant
If snowball bushes have been container grown they can be planted any time during the growing season, though more water and care are needed to get shrubs successfully started during very warm periods. According to Clemson University Extension, the ideal time to plant shrubs in the Southeastern U.S. is during the fall because milder temperatures allow root growth to continue through the winter so plants are already well established when spring arrives and new top growth begins. Fall planting is optimal also in many parts of California and other mild winter areas. Where winters are severe, spring planting is preferable, so plants have many months to get established before winter's onslaught.
Well-drained, slightly acidic soil is ideal for snowball bush, but the shrub also tolerates alkaline soils. It has great drought tolerance once established. Work slow-release fertiliser into the soil at planting. Also fertilise shrubs every year after flowering. Like other viburnums, snowball bushes need at least six hours of full sun for good bloom. Prune shrubs immediately after flowering to shape them and to remove dead, weak or damaged stems. Larger cultivars can grow truly massive. Prune them back to a height of 2 or 3 feet every few years to maintain some control, though this will cost you the following spring's bloom.