Growing outdoor plants for winter interest takes some planning. The first step is to decide if you are willing to use cold frames to protect outdoor plants, such as winter vegetables, or if you want something that looks good, but does not require any additional work. The USDA hardiness zone you live in will determine what types of outdoor plants for winter interest can be grown.
You may think of evergreens as plain green trees, such as those used for Christmas trees, that remain evergreen and have brown cones. During the holiday season, you can add lights or other decorations to these trees; they also make a great place for birds to nest. But evergreens used as outdoor plants for winter interest can add much more than this to the landscape.
Add a touch of gold to the winter landscape with a gold juniper or an oriental spruce with branches edged in gold.
If purple cones and silver-lined, blue pine needles sound more enticing, plant an Abies koreana 'Silberlocke,' commonly known as silver curls Korean fir tree, which is hardy in USDA zones 5 to 7.
The star of the winter garden is the camellia. Hardy in USDA zones 7 to 9, this is a necessary group of outdoor plants for winter interest if blooms are important. New cultivars are being cultivated that are hardy to USDA zone 6.
Camellia sports evergreen leaves and blooms in many sizes, shapes and colors. If you grow camellias, you can expect blooms from October through April. There are varieties that bloom during other times of the year as well.
Newer varieties are available that are hardy in USDA zones 6 and 7. If you grow camellias in these cooler climates, plant them in a well-protected area and mulch them well.
If you wish to grow vegetables year-round, you will find that you need to use cold frames and frost cover, especially if you garden in USDA zones 5 to 7. You can make a simple cold frame from four bales of straw laid out into a square, with an old window put on top to cover the opening in the center where the winter vegetables will grow.
Plant cool season crops such as potatoes, carrots, lettuce, spinach or mache, a European salad green, inside the straw bale cold frame in early August. Before the first frost arrives, place a frost cover over the plants and put the window on top of the straw bales. Metal hoops should hold up the frost cover so it does not touch the plants.
A light frost will improve the taste of plants such as kale and Brussels sprouts, so do not cover these plants with a cold frame until right before the first heavy frost.