Monday, November 19, 2012

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 now-classic The Garden in Winter.

Copyright 2012, Joseph M. Keyser

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