Gardening: Unusual plants for winter gardens
by Mary Robson, WSU Area Extension Agent
Guests visiting during December often comment on the "green" and "alive" look of maritime Northwest gardens. My family, here from Wyoming and Boston, don't expect winter to hold any garden intrigue, for their landscapes are clamped down in cold and snow.
But we surprise visitors with an astonishing range of winter plants that grow throughout December, January, and February. These are the plants that make constant gray skies more bearable.
Many of the flowering shrubs of winter are quite familiar--fragrant witch hazel, sarcococca, and various daphnes. Some blooming shrubs such as Camellia sasanqua and early rhododendrons also grace gardens. But what about some of the less-often-chosen plants that can intrigue us as we walk through nurseries this time of year? (By the way, one of the most calming and refreshing places at the busy holiday season is a nursery, with shrubs and blooming plants gathered for appreciation in cool shelters. Take time to walk through while selecting greens or a tree.)
Gardeners are often surprised to find that several fragrant shrubby honeysuckles bloom during winter west of the Cascades. These aren't the vines commonly found scrambling over southern garden walls. Shrub-forming, one of the most fragrant is Lonicera fragrantissima, blooming in milder spells of weather from mid-December to March. Small, cream colored flowers send the familiar, spicy honeysuckle scent into the garden. A twig of this one, blooming now, sits on my desk perfuming the room. L. fragrantissima becomes a gawky shrub, sending out sprawling branches to about six feet, and it belongs tucked behind other, more graceful plants. Its winter performance compensates for its awkward shape during the rest of the year.
Mahonia is often planted as a ground cover in shady, woodsy areas, the most common plant for this use being Manhonia nervosa. All mahonias do have blooms, but there are several that offer particular beauty for the winter garden. One that is planted to excellent effect at the Washington Park Arboretum in Seattle is Mahonia x "Arthur Menzies." At maturity, this plant forms a small tree, six to eight feet tall. The foliage is handsome, but what gives it real winter interest is knockout brilliant yellow flowers, held up on the branches, sometimes over a foot long. This is a valuable evergreen for mild-climate gardens. Another mahonia often planted is Mahonia x media 'Charity,' with pale yellow flowers.
Another plant with a local pedigree is the coast silk tassel, Garrya elliptica. This is, like mahonia, native to the west, and its claim to garden interest is the long, light gray-green catkins that emerge and dangle from branches. Garrya x issaquahensis, which was found in a personal garden in Issaquah, is hardy and adapted to garden use here, with long handsome catkins. The shrub has evergreen foliage and will tolerate dry summers once settled into the garden.
Daphnes of all sorts are relatively hardy here, several of them being definite additions to the winter garden. One that has bloomed satisfactorily in my Seattle garden for about six years is Daphne odora "Marginata," the variegated leaf daphne. It's about three feet tall, with a 3-foot spread, and retains handsome light green leaves edged with small clusters of pinkish white flowers that are, in my opinion, the sweetest of all garden flowers. The scent is clean and citrusy and spicy all at once. This is another plant that can scent a room with only a few blooms captured in a vase. This daphne requires good drainage, lots of porous soil around the roots, protection from sun and very little summer water.
The Daphne odorsa in my garden is underplanted with a selection of hellebores, perennial flowers with nearly evergreen foliage. Plant collectors have rediscovered hellebores, and nurseries will often carry several different species. One species that has been hybridized into dozens of handsome plants is Helleborus x orientalis, sometimes called Lenten rose for its bloom period of February and March. The Lenten rose flowers in various colors--red, pink, and white. Open flowers last for weeks in the garden. Give hellebore shade, compost in the soil and around the plants, and occasional summer water.
With these, and dozens of other winter-blooming plants, gardens in our area can produce small bouquets, excellent scents and growth to watch through winter. As I write this, the hellebores have fat clumps of buds formed at the crown, the snowdrops have begun to grow, and the daphne is in bud. In cold spells, all these plants will slow down, or stop, retreating until milder weather. But they recover and bring us all a welcome early spring.
Nursery visits will show you many of these plants, and more. To see a winter garden in perfection, walk through the Washington Park Arboretum during December, January, and February. The Joseph Witt Winter Garden has elegant, mature specimens of many of these plants, and more. To read more about it, look for Daniel Hinkley's comprehensive book, Winter Ornamentals, Sasquatch Press, 1993. This book and a gift certificate for winter plants would please any dedicated gardener.
Visit WSU's Agriculture Site on the World-Wide Web at http://www.cahe.wsu.edu.