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Shrub Profiles—Six Spring-flowering Wonders With Year-round Appeal
Plants & Gardens News Volume 16, Number 1 | Spring 2001
by Richard L. Bitner
As a group, deciduous shrubs are perhaps the most adaptable and easygoing of plants. Unlike annuals, they don't seed around the garden. And unlike so many perennials, they don't require constant division. The roots of most shrubs are sufficiently long to make the plants resistant to drought, which is good news considering recent fluctuations in our weather. Many are suitable for wet sites, too.
The relatively small size of shrubs makes them a movable feast for those of us who rearrange our yards as often as we do our living rooms. Planted thoughtfully, they lend important structure and framework to the garden and act as a backdrop for the passing lively displays of bulbs, perennials, and annuals.
"But," interjects Uncle Henry, the garden curmudgeon, "today's enlightened gardeners are interested in plants that enliven their borders for more than just one season. After they flower in the spring, aren't shrubs just an eyesore for five months?"
Well, beauty of bloom is certainly the reason why many shrubs are planted—you would never plant a lilac for its foliage. However, Uncle Henry, take time to consider the following spring-flowering shrubs, which have year-round appeal and, in my opinion, would be worth growing even if they never bloomed at all.
Viburnum trilobum
Viburnum trilobum (American cranberry bush)
Azaleas and rhododendrons are just fine, but for me the premier spring-flowering shrubs are the viburnums. They are the favorite plants of many horticulturists, but are strangely underused in our gardens. One lovely viburnum not often cultivated, though indigenous from New Brunswick to British Columbia and south to New York, is V. trilobum, (also known as V. opulus var. americanum), American cranberry bush. In late spring, the shrub is covered with typical flat-topped, creamy white viburnum flowers. Its heavy, bright-red fruit display, beginning in September and holding into February, is its best feature. The berries provide a feast for birds such as ruffed grouse, brown thrashers, cedar waxwings, bluebirds, and cardinals, as well as other wildlife like red squirrels and chipmunks. Gardeners can enjoy eating the fruit, too—it makes a fine ruby-colored jam with a distinctive flavor. The dense foliage of V. trilobum provides cover for turkeys, grouse, and pheasants. It is also a larval food source for the spring azure butterfly.
In suburban and rural gardens, American cranberry bush is excellent for integrating designed areas with the surrounding native landscape. It will grow in sun or partial shade, in well-drained, moisture-retentive soil, but will not thrive under prolonged hot, humid conditions. The cultivar 'Wentworth' has an upright habit (growing 12 feet in height) and makes an outstanding plant for screening and hedging, while providing white spring flowers, heavy fruit display, and burgundy fall foliage color.
Viburnum nudum 'Winterthur' (Smooth witherod)
Though V. trilobum is a strong contender for the title, the must-be-in-every-garden viburnum is V. nudum 'Winterthur'. The wild type is native from Long Island to Florida and west to Kentucky. This cultivar was selected in 1961 by Hal Bruce of the Winterthur estate garden in Delaware and received the Pennsylvania Horticultural Society (PHS) Gold Medal Award in 1991. As with V. trilobum, it is the fruit display, starting in late September, that will rivet the attention of your visitors. When the berry clusters are ripening, they progress through a series of color changes: green to white, then blushing pink, and finally blue to bluish black. It is not unusual to find this viburnum decorated with masses of multicolored berries. The fruits are particularly attractive alongside the plant's very handsome red to reddish purple fall foliage, and they can persist into February.
V. nudum 'Winterthur' has a formal habit: dense, uniform, upright, and rounded. Although it does well in normal garden conditions, it is found growing along streams in the wild and thus appreciates somewhat moist, acidic soils, in full sun or partial shade. Its lustrous foliage looks clean the entire growing season. The shrub needs no pruning and can be grown as a specimen or a low screen. I grow it near an Acer griseum (paperbark maple), with Amsonia hubrichtii (Hubricht's bluestar), Helleborus argutifolius (Corsican hellebore), and Ceratostigma plumbaginoides (plumbago) for companions. One cautionary note not always mentioned in catalog listings: this cultivar doesn't self-pollinate, so plant a straight species V. nudum nearby to ensure good setting of fruit.
Myrica pensylvanica (Northern bayberry)
Myrica pensylvanica
This plant grows in sandy, acid soils and exposed, dry infertile sites in coastal regions from Nova Scotia to Florida. It's an underused ornamental shrub that will cope well in such seemingly hopeless urban sites as curbside containers and parking lot islands. The plant fixes atmospheric nitrogen into the soil (like many legumes, to which it is not related). Bayberry will even tolerate salt spray!
It is a handsome shrub in all seasons. Although the April flowers are not showy, the lustrous leathery green foliage is aromatic when crushed and looks attractive all spring and summer. Abundant gray-white fruits cluster in great numbers along the stems of female plants (the species is dioecious) and persist from September through April. Of course, the berries can be boiled to extract the wax, which is then used to make scented bayberry candles. But I grow the shrub for its ecological benefits: the beautiful cecropia moth feeds on bayberry as a caterpillar. The bayberry's thick growth provides nesting cover for wildlife; its waxy-coated fruit and nutlet seed are eaten by many birds, including bluebird, catbird, meadowlark, thrashers, and vireos.
Bayberry is one of the most versatile of landscape shrubs, equally at home in mass plantings, mixed borders, or informal foundation plantings where it combines well with evergreens. It is an outstanding choice for seaside locations but is also growing to great effect in containers near City Hall in downtown Philadelphia.
Vaccinium corymbosum (Highbush blueberry)
This shrub is native from Maine to Florida and is perfect for areas in the garden that tend to stay wet. It's best planted alongside other acid-loving plants in a marshy border. The urn-shaped late-spring flowers are not particularly ornamental, but they provide edible fruits in the fall. The fall foliage display is stunning, with varied hues of orange to red. Many cultivars of this species have brightly colored yellow to red twigs in the winter. Check with your county Extension agent to learn about the best cultivar for your area, and plant more than one of them for cross-pollination.
Vaccinium corymbosum transplants easily thanks to its fibrous root system. I grow it for the many quarts of late-summer blueberries. A hungry gardener might cover the plants with netting to protect berries from foragers and then make pies, pancakes, jelly, and, of course, muffins—but my berries are for the birds. Blueberries are an important food source for grouse, scarlet tanagers, thrushes, woodpeckers, blue jays, bluebirds, catbirds, and numerous other songbirds. A friend of mine uses blueberry as a foundation planting to draw winter birds closer to her study window. She must keep her plants pruned, however, or they would reach up to 12 feet in height. The blueberry's foliage is a larval food source for hairstreaks and elfin butterflies.
Lindera obtusiloba (Japanese spicebush)
In the wild, Lindera benzoin is often associated with highbush blueberry. It is one of our first native shrubs to bloom, creating a haze of yellow throughout the forests of the eastern United States. L. benzoin flourishes in wet woods, along stream banks, and around springs. Its foliage and twigs give off a pungent aroma when scratched, hence the common name. Despite the fact that this shrub produces vivid red fruit against bright yellow foliage in the fall, it is not often used in planned gardens.
A shrub that I think is even more garden-worthy is the Japanese spicebush, L. obtusiloba. Although introduced by E.H. Wilson in 1907, this rounded understory treasure is still little known. Its soft yellow flowers appear earlier than those of L. benzoin, often while snow is still on the ground. It can grow to 15 feet and look like Cornus mas (Cornelian cherry) in flower. But there is no mistaking its remarkable, variably lobed leaves, which turn an intense, uniform, brilliant golden yellow in October, even in part shade. The fruits of both spicebushes are eaten by at least 24 species of birds.
Enkianthus perulatus (White enkianthus)
For spectacular scarlet fall color, nothing beats Enkianthus perulatus. It is a mounded, slow-growing shrub with wonderful layered branches that retain their ground-level foliage, even when mature. In May, it is covered with white, nodding urn-shaped flowers that give it a subtle oriental appearance. This white enkianthus is a very elegant shrub that should be used as a feature or specimen within the mixed border. Because of its small size (up to 4 feet high) and slow growth rate it is perfect for smaller gardens, foundation plantings, and hillside or rock gardens. Few shrubs are more charming than this species in full bloom, and the brilliant red fall color is extraordinary. The cultivar 'J. L. Pennock' has an exceptionally long season of fall color and received the PHS Gold Medal in 1999.
So you see, Uncle Henry, selecting shrubs that change dramatically in the course of a year offers you the chance to enjoy some striking effects in the garden that cannot be achieved by the usual spring-flowering plants alone. Watching the transition from flowers to fall color to fruit display is one of the great attractions of having a garden. Often the end of a shrub's natural cycle of growth is as inspiring as the beginning.
Although a board-certified anesthesiologist by trade, Richard L. Bitner is also eminently qualified to fill out a prescription for gardeners looking for new planting ideas. He is a lecturer on deciduous flowering shrubs at Longwood Gardens (he's also a garden guide there) and an instructor in herbaceous plants at the Arboretum School of the Barnes Foundation. His writing and photographs have appeared in Green Scene, Horticulture, The American Gardener, and Plants & Gardens News. Richard is a member of the Pennsylvania Horticultural Society's Gold Medal Plant Award Committee.
Illustrations by Bobbi Angell.