I'm the first to admit that partnering plants in winter conditions is a challenge. Winter gardening in milder climates makes use of plants that retain their foliage and produce flowers in cold—but above-freezing-temperatures. In most of frosty Canada, however, the deciduous foliage and absence of petals makes for an austere scene from November through April. But despite the hardships of frost and winter dormancy, the season is an opportunity to highlight the attractive characteristics of plants in a simple, direct way. Creating these complementary plant combinations requires planning well in advance of the cold months, and an eye for seeing the structural and ornamental features plants will present in winter.
In northern climates, conifers and broadleaf evergreens are the backbones of the winter garden and can anchor many seasonal plant combinations. Almost every coniferous specimen changes colour in temperatures below freezing, providing diversity to even commonplace plantings. Cedars and yews darken, displaying black tones; the blue-green and powdery grey-blue tints in some pines and spruce deepen; and many junipers take on plum or purple-grey hues. A few others, such as ‘Pincushion' and ‘Winter Gem' Korean boxwoods and Siberian carpet cypress, change to shades of bronze. These low-growing, copper-toned plants are good partners for the cinnamon-coloured, exfoliating bark of paperbark maple. Adding a clump or two of Japanese kerria, with its thin, arching, apple green stems, makes a welcoming winter grouping in a corner of the front lawn.
There are also hybrid conifers bred to keep their bright colours in cold temperatures, including ‘Green Mountain', ‘Green Gem' and ‘Green Velvet' boxwoods, as well as Emerald cedar and ‘Mint Julep' juniper, all of which stay vibrantly coloured in deep cold. Indeed, much enjoyment can be had with cedars in winter, pairing the bright green Emerald with the dark crimson bark of red osier dogwood. Even more colour radiates from golden yellow ‘Sunkist' cedar, especially when it's complemented by yellowtwig dogwood. But the full colour blast comes from ‘Winter Beauty' dogwood, which starts off fiery orange-yellow at the base of its canes and spreads to pink and red at the tips. This brightest specimen is cooled with a soothing skirt of ‘Mint Julep' junipers. (These dogwoods display their most brilliant coloration on new wood, so cut out a third of the oldest canes at their bases each spring to promote bright, new growth.)
A more complex grouping partners the deciduous corkscrew hazel—a shrub that reveals its contorted, woody tendrils in winter—with the low-mound form of globe blue spruce. Powder blue during the growing season, it deepens to steel blue in cold weather. The ensemble is complemented by a thick clump of perennial Autumn Joy stonecrop, sturdy enough to withstand wind and ice, and to hold perfect little pillows of snow atop each flower head.
I like to have some worthy specimens that stand alone and make strong visual statements in winter, but even these solitary plants benefit from subtle partnerships. To my eye, one of the most beautiful trees is fern-leafed beech. In winter, its elegant, pointed buds are often highlighted against a robin's egg-blue sky. Enhancing this scene are a similarly delicate fringe of dark green periwinkle—its bright, pointed leaves matching the shape of the tree's buds—and some clumps of tall ‘Karl Foerster' feather reed grass flower stalks.
Photo: Top, rhododendron and middle right, unidentified berries in winter