Planning the Winter Landscape – Plants for Northern Zones

The northern zones of the United States contain a diverse range of climates and geography, but generally speaking they include a shutting down of the growing season for at least four months of winter, temperatures that can fall well below 32 degrees F, and shortened days of minimal sunlight. Consequently, most gardeners learn to forgo color in the garden, and try to content themselves with visions of spring while surfing through the many catalogs that begin to appear right after Christmas.

However, don’t forget that there is more to the garden than colorful flowers. There is shape, both in silhouette against the snow and in shadow in moonlight, and there is texture, in bark and needles and branch. There may also be some late fruit such as berries, which feed the birds from autumn into winter. If you’re a bird watcher, the attractiveness of your landscape for them, with plants that provide shelter and food, will be a strong consideration. And yes, there is color as well.

Blue Holly (Ilex meserveae x)

The blue holly, originally developed by Mrs. Leighton Meserve of New York by using two species, Ilex rugosa and Ilex aquifolium, is considered the best cold hardy broadleaf evergreen shrub. Its attractive deep color and red berries provide interest in the winter garden and will continue to provide pleasure as long as it is pollinated at the right time by planting both male and female plants of the same named cultivar. Some popular versions are ‚”Blue Boy” and ‚”Blue Girl”, ‚”Blue Stallion” and ‚”Blue Maid”, and ‚”China Girl” and ‚”China Boy” which have lighter green foliage and are the most cold hardy of all.

Proven Winners announced this fall that they are offering the Castle Ilex series: ‚”Castle Wall” and ‚”Castle Spire”. These varieties are compact, have a narrow form, and make great hedges or foundation plantings.

Dwarf Cedar of Lebanon (Cedrus libani ‘Nana’)

While calling this winter-hardy shrub a ‚”dwarf” might seem silly (it grows to 15 feet with a spread of 15 feet!), remember that its full-size forebear can easily reach 100 feet in its native climate. The dwarf Cedar is a low-growing, low maintenance plant with finely-textured foliage. It is an attractive gray-green color, and requires almost no pruning. The dwarf Cedar does require full sun, and even with tender care it is a slow grower. The Sun Valley Garden Center says ‚”Consider this a heritage plant, …it can live to a ripe old age of 100 years or more!” A group of great photos of the Cedrus libani ‘Nana’ can be found at GardenWeb’s Conifers forum.

Another interesting function of the dwarf Cedar of Lebanon is its use as a bonsai. Full-size Cedars of Lebanon are strikingly dramatic in shape and often live in harsh landscapes. Re-creating the drama of such surroundings in miniature with a bonsai version of the Cedrus can be a fascinating pursuit.

Red Osier Dogwood (Cornus sericea)

Although in all other respects the Red Osier is rather ordinary, it acquires its happy place in the winter garden by virtue of its bright red branches and twigs. When newly sprouted, the stems are dark red, then fade to gray-green, and then are transformed back to bright red when autumn arrives and its leaves have fallen.

The Red Osier is tolerant of wet soils and is often found in swamps, riparian zones and the edges of forest. It does prefer moderate to full sun, and rich soil. Flowers are small, white and not very showy, and there are white or grayish-white berries. This is a plant that is extremely cold-hardy (down to -320F in laboratory tests) because of its water-retention, which actually lowers its freezing point.

Winter hardy plants for northern zones

There can be many sunny days during northern winters, and once the solstice passes the days begin to grow longer. While you are counting the days until the last snow and frost in your area, rest your gaze on the color of the red osier, the texture of the dwarf Cedar of Lebanon, and the striking contrasts of the blue holly.