Winter containers provide interest

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By Susan Brown, County Extension

It has finally started to cool down and look and feel more like winter. It is not quite time to throw in the towel though, if you enjoy gardening. Winter containers can be a great challenge, but a rewarding one. Containers can provide year-round interest, depending on the plants you choose.
For a plant, life in a container is different than living in the ground. Containers provide excellent drainage, but the plant depends on you for water and nutrients. Shrubs and larger perennials often stay smaller in a pot, though this depends on the plant, climate and container. Remember, plants in pots are not insulated like the ones in the ground.
The general rule of thumb for container-plant survival through the winter is the plant should be hardy to two zones colder that your USDA hardiness zone. I like a challenge and always try to winter-over plants that supposedly do not survive.
I have had some successes and failures as well. Make sure the pots you select are frost-proof. Choose a container with a drainage hole in the bottom, made of fiberglass, lead, iron, heavy plastic or stone. Most terra cotta will crack in cold temperatures, but I have had luck with glazed pottery. Stop feeding your plants about six to eight weeks before your first frost date. This will prevent any tender new growth, which would not survive the winter.
 Let’s talk about plant selection
In containers, you have three main parts: pillars, spillers and fillers. I always pick the pillar first. This will be the plant that will anchor the pot and also provide balance within the design.
One of my favorite winter interest plants would have to be the Harry Lauder’s Walking Stick, Corylus avellana Contorta. This upright, tree-like shrub has heart-shaped leaves and strongly twisted, spiraling limbs. Pendent yellow catkins are borne in late winter and early spring.
If possible, purchase trees grown on their own roots to avoid rootstock suckers. A newer cultivar, Red Majestic, bears burgundy colored new growth, so it has greater summer appeal.
Another great pillar would be Nandina domestica. This plant has huge panicles of white flowers that turn to attractive, orange-red berries that are held against bright, green, lacy foliage making nandina a handsome plant and earn it another common name, the heavenly bamboo. The bright berries are beloved by birds and attract mockingbirds, cedar waxwings and robins, while the flowers are attractive to bees. Many people use this plant as a fresh-cut green for the holidays.
A great spiller to use in a winter container would be creeping jenny. This plant cascades over the rim of a pot with its golden coin shaped leaves and contrasts nicely with burgundy tones. Some varieties of sedum are evergreen and make a nice spiller as well.
The filler plants can be pansies, ajuga, black mondo grass, heuchera or even evergreen hollies. Their job is to be low growing and provide interest below the taller plants in the container.

horticulture agent with the Brunswick County Extension Service. Call 253-2610 or e-mail susan_brown@ncsu.edu.