Versatile Viburnum

BY PJ GARTIN

I can’t figure out why people aren’t as smitten with viburnum as I am. It is mostly an evergreen shrub, blooms from late winter to early spring and comes in over 120 species plus numerous varieties. Several cheerfully embrace our sultry summers, and mostly ignore an occasional bone-chilling winter. Yet, I seldom see viburnum in Charleston landscapes and this drives me nuts. Fall, our best time for planting, is here. Think about it: Do you really need another ligustrum or Japanese yew in your garden?

When it comes to horticultural practicalities, Viburnum spp. can’t be beat. It is beloved by nurserymen for its disease and insect resistance and, if you choose wisely, requires a minimum of pruning.

However, like all plants, individual species have their own quirks and personalities. Take Awabuki viburnum (V. awabuki) for instance.

Viburnum awabuki
Height: 10 – 15 feet (20 feet is possible)
Spread: 4 – 6 feet
Light: sun or shade
Moisture: drought tolerant once established
USDA Hardiness Zone: 8 – 9 (possibly 7–9)

Awabuki’s abundant, shiny, dark green leaves make it useful as a screen, but you’ll have to prune it frequently to keep it under control in a small space or near a structure. This shrub can get quite large—10 to 20 feet tall. However, because its growth habit is upright and pyramidal, it looks spectacular untended and planted in clusters of odd-numbers.

By far the most reliable Awabuki for Charleston gardens is a cultivar named ‘Chindo.’ Chances are that’s the one you’ll find at local nurseries. If you intend to use it as a solitary specimen, consider tucking another one somewhere in your landscape. Doing so will reward you with better flowering because ‘Chindo’ performs best with a mate. Although it sends out attractive white flowers in early summer, this Awabuki is coveted for its bright red, pendulous berries that appear later in the season. Provide your shrub with a pollinator to ensure a good fruit set.

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Awabuki is frequently confused with other kinds of viburnum, especially V. odoratissimum. The reason I’m telling you this is that Awabuki is sometimes accidently sold wearing the wrong tag. One way to tell if you have a genuine Awabuki is to crush a leaf. If it smells bad, it’s V. odoratissimum. If you purchase it anyway, you’ll eventually discover that it’s not as cold hardy as Awabuki.

Then there’s Chinese Snowball viburnum (V. macrocephalum)—sometimes called CSV. This viburnum is noted for putting on a spectacular springtime flower show with an encore performance in the fall. The flowers are similar to those of mophead hydrangeas—ball-like and 4 to 8 inches in diameter. The blossoms first appear greenish but quickly turn to a snow white. The flowering period should last as long as six weeks in most Charleston gardens; blooming into early summer.

Viburnum macrocephalum
Height: 12 – 20 feet
Spread: 10 – 15 feet
Light: nearly full sun with afternoon shade
Moisture: requires regular watering
USDA Hardiness Zone: 6 – 9

CSV is beautiful even when not in bloom. It has a rounded growth habit that spreads 10 to 15 feet in width and 12 to 20 feet in height. The leaves are light green and 2 to 4 inches long. Although plant tags often suggest that CSV performs best in full sun, give it a respite with a healthy dose of afternoon shade. Also, plant it in well-drained soil with moderate fertility. If this viburnum gets out of hand, prune it immediately after flowering but don’t overdo it. Like the standard cultivars of mophead and lacecap hydrangea, CSV blooms on second-year wood.

Another winner for Charleston gardens is Sandankwa viburnum (V. suspensum). It resists drought and loves sandy soils and, because of a moderate to good salt tolerance, makes a good beach shrub. This viburnum is capable of getting 12 feet tall and makes an interesting specimen, screen or hedge plant. Its leaves are broad and leathery, and the nearly inconspicuous flowers appear in early spring. The flower buds are borne on the previous season’s growth, so keeping it clipped into a hedge will eliminate flowering, and you can postpone pruning until blooming ends. The berries that appear in late summer are attractive. They begin red, then gradually mature to black by autumn.

Viburnum suspensum
Height: 6 – 12 feet
Spread: 4 – 8 feet
Light: full sun or shade
Moisture: drought tolerant
USDA Hardiness Zone: 8 – 9

Although Sandankwa tolerates heat, horticulturalist John Millman of Hyams Garden Center on James Island says that the shrub likes a little more shade than sun and will actually thrive in shady areas. Sandankwa can be used almost anywhere without worry, but Millman warns that it has a peculiar trait. “When it’s pruned, it gives off an unpleasant odor, slightly reminiscent of cooked bacon,” he says.

If you now find yourself pining for a viburnum, but have no room for a tall or medium one, then consider this little cutie: Mrs. Schiller’s Delight (V. obovatum ‘Mrs. Schiller’s Delight’).

Viburnum obovatum
Height: 3 – 4 feet
Spread: 3 – 4 feet
Light: sun or shade
Moisture: drought tolerant once established
USDA Hardiness Zone: 6 – 9

Millman calls it “an excellent choice for Charleston landscapes.” This dwarf native has small, 3/4-inch leaves and very small flowers that bloom in spring. It grows 3 to 4 feet tall and just as wide. Gardeners find it a refreshing alternative to our ubiquitous boxwood (Buxus spp.) or dwarf holly.

PJ Gartin is a garden writer and landscape photographer in Charleston.