Garden leaves have been raked (mostly) and incorporated into the compost bins. Spring blooming bulbs have been planted. It is time for the gardener to transform outdoor containers into winter gardens. 

If you live in the Northern Virginia area, your garden is most likely dominated by the shade of lovely oaks, tulip poplars and other large deciduous trees. Gardeners in our area can maximize available sunshine by incorporating large containers planted with annuals and perennial bloomers into garden beds or hardscaped areas like patios and driveways.

But what does the gardener do with these large urns and pots when summer is over?

Colorful blooms and foliage can continue to delight the gardener even in the winter if cold hardy plants are used. I have had success combining huechera, ornamental kale, ornamental grasses, pansies and groundcovers such as creeping jenny, English ivy, and creeping euonymus into my outdoor containers—these plants provide texture, color and in some cases blooms throughout the fall and winter.

There are a few rules to follow to ensure that your containers continue to give pleasure well into the spring.

1. Choose a container that won’t crack from the freezing and thawing sure to happen in our area. Porcelain, ceramic and terra cotta pots are most problematic because the swelling of moisture rich soil as it freezes can exert enough pressure against the pot to cause cracking. Iron, stone, concrete, wooden and fiberglass containers are more likely to withstand freezing temperatures.
2. Choose plants that are hardy at least two zones colder than our area. For us in Northern Virginia that means plants that are hardy to zone 5b—check the garden tags on plants in the garden center. I have included a link to the interactive USDA hardiness zone map for further information.  Some plants I have found to be hardy are dwarf arborvitae, dwarf evergreen holly, dwarf juniper, “green gem” boxwood, ornamental kale, yucca filamentosa, sweet flag, ornamental grasses, pansies, violas, primroses, ivy, heuchera, heucherilla, creeping jenny, creeping euonymous, and ajuga. I combine these plants with early (spring) season blooming bulbs such as crocus, daffodils and grape hyacinth to extend the life of the container into spring.
3. Plant your container early enough to give the new plants several weeks to become established before the first hard freeze. If the weather is dry, water the containers once a week, otherwise check on them every few weeks to make sure the soil is moist. Once the soil freezes, you no longer need to keep watering.
4. Containers can be “freshened up” for the December holidays by pushing cut boughs of holly, magnolias, or evergreens into the soil; remove these cut boughs and branches in January.

So give thanks for the lovely weather and warmer temperatures expected this coming week, and spend some time in your garden potting your large urns and containers with plants that will delight you when the cold winter weather arrives.

Gardeners can find more ideas for fall and winter container gardening at Green Spring Garden Park Gardener’s Holiday Open House on Sunday, December 2, 2012, from 12pm to 4pm. In addition to ideas for winter gardening, you will find wreaths, greens, bows and tree ornaments for sale, as well as toy trains running throughout the grounds, a special holiday exhibit in the Historic House, a puppet show, and fresh baked breads for sale.

Gardeners who prefer to incorporate cut branches of evergreens rather than live plants in their outdoor containers can take advantage of a free seminar being offered by Merrifield Garden Center is at their Fair Oaks location on Saturday, December 1^st at 10:00am. Merrifield Plant and Design Specialist Peg Bier will be creating displays using cut branches of cedar, boxwood, holly, magnolia and other plants.

Eleni Silverman is a Master Gardener, President of the Belle Haven Garden Club, Chair of the Landscape Committee at Thomas Jefferson High School for Science and Technology and author of the garden blog "Belle Haven Garden Maven." She is sole proprietor of The Well Tended Garden, providing garden grooming, coaching and design.  She admits to a fascination with all things gardening, believes even compost is engaging, and will eagerly discuss the relative merits of leaf mold versus hardwood mulch.