Blooms & Branches & Berries, Oh My!

You can beat the blahs of a winter landscape by remembering the three B’s of off-season gardening: blooms, branches, and berries. Admittedly, there are only a handful of introduced plants, and even fewer native species, which bloom and provide colorful relief during the gray days of mid-winter, with the striking and noteworthy exception of witch hazel (Hamamelis virginiana), alternately called common, fall- or winter-blooming witch hazel.

Our native variety is a relatively slow-growing small tree or upright shrub which begins its horticultural display in autumn with yellow fall foliage which soon turns to orange and golden-brown, and proudly heralds the beginning of its late-season blooming period. After the leaves have fallen, clusters of small, soft-scented yellow flowers appear along the branches from October through December. Each spidery clump consists of four twisted, fringe-like petals not quite one-inch long. Interestingly, the lemon-yellow ribbons tend to fully unfurl on warm sunny days, when we are lucky enough to get them, and, like most of us, curl up into a more compact mass when the weather turns cold and threatening.

More than a dozen non-native witch hazel cultivars have been gaining in popularity among winter gardeners, with dramatic new flower colors ranging from ruby-red and copper, to burgundy and bright orange-yellow, and featuring significantly later blooming periods, even into February, and a stronger fragrance. These low-maintenance hybrids are typically crosses of Chinese and Japanese witch hazels, and include favorites like ‘Jelena,’ which combines brilliant fall foliage in November with an encore of coppery red blooms as late as February and March, and ‘Arnold Promise,’ a brilliant yellow late-blooming cultivar developed by the Arnold Arboretum.

For more year-round color, garden designers have long cherished the subtle and sometimes spectacular twigs and trunks of our native dogwood species. Leading the list is red osier dogwood (Cornus sericea formerly stolonifera), also aptly called red-twig dogwood. This fast-growing specimen is a cousin to the white flowering dogwood with which we are more familiar, and quickly forms attractive thickets ideal for screening or habitat plantings.

Although its white flowers and berries are popular among songbirds like vireos, finch, and pine warblers, they are somewhat dull in appearance, a deficit more than offset by its brilliant red twigs and reddish-green bark. After a snowfall, nothing stands out in a winter garden more than the vivid red stems which seem to shoot up from a pure field of snow. In addition, goldfinches have been known to favor this species for a nesting site; their bright feathers flitting among the branches will ornament both shrub and garden alike.

Another attractive option is the yellow-twig dogwood (‘Silver and Gold’), a cultivar of red osier, renowned for its green and white variegated foliage, good autumn color, and, above all, bright golden bark.

Silky dogwood (Cornus amomum) takes its name from the grayish hairs along younger branches and flower buds, and features reddish-purple twigs and darker mahogany-brown bark. Silky dogwood also presents lovely flat creamy-white clusters of flowers in the spring, followed by bluish clusters of fruit in late summer, often lasting through fall and possibly winter.

The final and perhaps most important components for a winter garden are berries. Berry-bearing small trees and shrubs add a surprising splash of color and seem to stand out equally well against either snow-covered garden beds or leaden winter skies. Of equal importance, berries support scores of migrating and over-wintering birds, some of which, like cardinals, woodpeckers and bluebirds, add their own element of lively color to a landscape.

Topping most lists is winterberry or “possum haw” (Ilex verticillata), a deciduous native holly with upright, spreading stems reaching up to ten feet in height. Clusters of white flowers appear in April through May, producing bright reddish-orange to deep red berries which last through the winter, avian appetites notwithstanding. Keep in mind that winterberry is dioecious, having male and female flowers on respective plants, and requiring at least one male shrub for every three to four female specimens.

Native viburnum species, such as Arrowwood or American cranberry (V. trilobum), provide attractive clusters of white flowers in spring, brilliant fall foliage, and berries ranging from bright red to bluish-black in fall through winter. The species also provide an important source of fruit to more than fifty species of songbirds in our area.

Both red and purple chokeberries (Aronia species) take their name from colorful fruits which offer brilliant red and scarlet foliage in autumn, followed by bright red or blackish-purple fruits throughout the winter. For best effect, it is generally recommended that chokeberries be planted in clusters for a natural, sprawling effect.

Sumacs are best known alongside roadways, but smooth sumac (Rhus glabra) makes for attractive massed plantings or “colonies” in home landscapes, like the chokeberries. Autumn foliar displays, similar to chokeberries, are replaced in winter by greenish-crimson fruit which can last into spring and are keen favorites of bluebirds, catbirds, robins, and mockingbirds.

These, of course, are only a sampling of the (mostly) native species which can be used to adorn a winter garden. There are also evergreens with variegated foliage, ornamental grasses featuring golden orange stems and graceful tufts of seedheads, and so much more. For an expanded tour of the subject turn to Rosemary Verey’s classic The Garden in Winter.

Copyright 2014, Joseph M. Keyser

Versatile Viburnums for a Vibrant Landscape

Gardeners in the temperate zones of North America can select from hundreds of small trees and shrubs which will readily flourish in our climate. However, among all the choices there are only a handful of “must-have” species, with viburnum at the very top of that fairly short list.

There are approximately 200 species of viburnum worldwide, with more than 120 species in North America alone. Locally, in the Mid Atlantic region, our native landscape offers several absolutely dazzling specimens of viburnum that are suitable for almost every yard and situation, including Mapleleaf, Arrowwood, Possumhaw, and Blackhaw Viburnum (Viburnum acerifolium, V. dentatum, V. nudum, and V. prunifolium).

Michael Dirr at the University of Georgia writes in his landmark Manual of Woody Landscape Plants: “A garden without a viburnum is like life without music and art.” Dirr’s sentiment simply reflects the fact that it is difficult not to fall in love with viburnum. After all, we are talking about a species which is drought-tolerant and capable of handling dry soils, while it also thrives in moist, sometimes wet conditions.

The viburnum cited above will shine in either full sun of partial shade, making them ideal as either specimen plantings, or tucked in among other shrubs in a woodland garden.

Like most members of the Caprifoliaceae (honeysuckle) family, they are virtually pest-free and tolerant of pollution and harsh urban conditions. They can be trimmed and shaped to form an elegant privacy screen or hedge, or left alone to spread or “naturalize” across a wild, informal landscape.

But these noteworthy considerations are only horticultural nuts and bolts. Viburnums are easy to love because they are simply lovely.

Our native species all feature small white or creamy-white flowers appearing in flat-topped clusters or cymes roughly three or more inches wide. Actually, yellow stamens glowing against the white petals create the creamy color in both the Mapleleaf and Arrowwood shrubs. Some closely related viburnum species are even credited with pink or rosy blooms. The flowers typically appear in April through May, with each inflorescence lasting about two weeks.

But the show does not end in spring. While the flowering activity is somewhat reminiscent of our native dogwoods, the autumn foliage encore puts Cornus florida to shame. Depending on the species and growing conditions, fall leaf colors range from chartreuse and yellow, to orange, pink, red, burgundy and deepest purple. Moreover, the flowers will form drupes or berry-like fruits in attractive clusters from late summer through fall, which might last into winter, depending on avian appetites. The drupes range in color from a delicate porcelain-blue to purple and black.

Naturally, each of our featured viburnum have unique characteristics worth noting. For example, Mapleleaf Viburnum is decidedly a small multi-stemmed shrub, generally growing at a medium rate to between three and six feet high, with about the same spread or width. The species is known for its suckering ability, whereby shoots sprouting from the shrub’s base help it spread into a dense clump.

In fact, you might well consider planting a Mapleleaf for a hedge rather than turning to invasive species like privet, burning bush, or thorny barberry. Mapleleaf handles pruning easily, and can be kept in-bounds by mowing over tender suckers which might pop up in turf areas. This species can be easily propagated from cuttings taken between June and July. Buy just a couple of containerized plants and you can have a nursery-full in about a year.

Arrowwood is much like a big brother to Mapleleaf, sharing many of the former’s growth habits, although it can reach between eight and 13-feet in height, with branches arching out up between ten to 15-feet. Arrowwood also tends to grow in masses, making it another contender for a native hedgerow or screen.

Interestingly, many gardeners like to prune Arrowwood back to a single leader, encouraging it to behave more like a small specimen tree. Certainly its flowers, fruits, and autumn color establish it as a substitute for dogwoods, which are now under attack by fungal foes and insect-borers, and a fit companion for other woodland natives like Amelanchier and redbud.

Like all viburnum, Arrowwood is a phenomenal addition to any backyard wildlife habitat. However, as the shrub is “self-incompatible,” meaning that it cannot pollinate itself, you should plant at least several different specimens to ensure a dramatic and abundant display of fruit. The cedar waxwings, cardinals, and brown thrashers will thank you with a chorus of songs and whistles.

Arrowwood is also easily rooted, allowing you to propagate an entire shrub border from its ample supply of stout suckers. Indeed, the shoots sent up from the base of the shrub were so prized by Native Americans that they used them to make arrow shafts, from which this viburnum’s common name arises.

Possumhaw, also called Smooth Witherod, grows somewhat larger than Arrowwood, up to 20 feet, and can be decidedly more tree-like, featuring a rounded crown with a considerable spread. It also features long-stemmed, flat clusters of small, creamy white flowers which first start appearing in May.

The common name for this species denotes the popularity of its long, dangling clusters of fruits among opossums, although other small mammals such as squirrels, rabbits and chipmunks, as well as songbirds, make quite a feast from the half-inch long oval drupes, which start out green, quickly turning pink, and finally ripening to a dark blue or purplish-black and lasting throughout winter.

The species other common name, “withe-rod,” reflects that the tree’s smooth grayish-brown twigs are strong and flexible, and, in fact, were often twisted together to form a rope to gather together sheaves of wheat.

One of the more lovely features of Possumhaw are its waxy, dark green leaves, perhaps the glossiest of any viburnum, which turn to a rich cinnabar (cinnamon to scarlet) in autumn. ‘Winterthur’ is probably the most popular cultivar currently and commonly found, having a more compact form, growing to about six feet, with aromatic flowers in spring and brilliant red fall color.

The last selection is the largest and most versatile. Blackhaw is the most like a small tree, growing up to 21-feet or somewhat more. Although it also produces suckers and can be multi-stemmed, for the most part it is a slow-growing tree with a rounded crown and a thirst for moist and wet soils.

Blackhaw is the best choice for a stand-alone ornamental, and is a superior substitute for invasive and troublesome species such as Russian and Autumn Olive, Bradford Pear, and many of the other popular Asian pears and ornamental cherries.

Blackhaw can be also be used as a tall deciduous screen or hedge, much like hawthorns, to which this species is often compared. It takes well to transplanting, which is helpful should you need to thin out a too-dense hedgerow.

From dry upland slopes to soggy floodplains, viburnum can provide privacy, habitat, and year-round beauty, adapting to most every type of soil and exposure.

Copyright 2009, Joseph M. Keyser