Your potted plants can also be perennials

The traditional approach of planting annual flowers with an upright foliage accent into patio containers is a staple of seasonal design and with good reason. It works well and looks great immediately. Substitute perennials for those traditional annuals and you open up fabulous new gardening opportunities.

Perennial varieties that are ideal for container gardens have been coming into the market over the past decade or so. Gardeners can now find a ready supply of plants packaged especially for solo or combo use in containers, selected for ease of culture and visual interest. Since perennials can be slow to start from seed, it's best to use partly or fully grown transplants for your containers at home. Local nurseries also carry a wide selection of small and large pre-planted decorative pots that busy gardeners can take home for immediate enjoyment.

Flowers are a favorite consideration in any planting. Perennials do tend to have a shorter flowering period than annuals so be extra selective when choosing perennial plants for containers. Make sure the plant has attractive features that carry on even when not in flower. Perennials like coral bells, hosta, brunnera, pulmonaria and penstemon 'Husker Red' all have beautiful flowers and equally beautiful foliage. They have good visual effect whether flowering or not.

Container-grown perennials can be purchased from the garden center as fully mature plants in gallon-sized or larger containers, or in smaller pots to be grown further at home. For maximum effect, plant them closer together than you would in the garden and pay close attention to watering needs, especially on hot sunny days. The bigger the pot the better. Perennials have relatively larger root systems than annuals and require a little more pot space.

At season's end, annuals go into the compost heap but perennials can be planted in the garden and covered with a thick winter mulch to establish them in their new bed. Extra-hardy perennials can be wintered over in weatherproof containers outdoors. For greatest success choose varieties that are one or two zones hardier than you would normally buy.

Containers should have adequate drainage and be made of materials that can stand alternating freezing, thawing and wet conditions. Terra cotta is generally not a good choice as it tends to flake and crack under winter conditions. Wood is a good all-season material and the newer synthetic materials, marketed for their year-round resiliency, come in a variety of colors and textures.

Whatever material you choose, the pot should have at least one drainage hole in the bottom. This is critical if you plan to overwinter your perennials in the pot.

Use a good potting soil rather than regular garden dirt. Mixes made specifically for use in containers are light in weight and drain readily. Many come with a complete fertilizer added. If not, you will need to apply a weak liquid fertilizer periodically, according to package directions.

Stop feeding your plants a month or two before your first expected frost date and don't fertilize again until the plants resume growth in the spring. Water only as needed until the soil in the container freezes with the weather, then stop.

I've had 100 percent success in overwintering hardy sedums and sempervivums in their pots. I set them on their sides up against the north foundation of the house and then cover the pots with leaves or straw. Setting pots on their sides prevents a deadly buildup of water over ice, which can rot plants during midwinter thaws. When early spring cleanup begins I set the pots back out on the deck.

Look for long-flowering perennials with neat growth habit and interesting foliage. These are ideal for using in pots. For extra added color all season long, mix in a flowering annual or two with your perennials. Add a trellis and you can grow small clematis varieties like 'Hendryetta' or 'Climador.'

Complimentary color schemes are always strong. Think glowing yellow-orange (coral bells 'Caramel') in a bright cerulean blue container. Very noticeable! Other complimentary combos are blue and orange, purple and yellow, and red and green. One single plant in a soft colored pot can be quite charming. Corydalis lutea with its tidy, fern-like foliage and butter yellow flowers from spring to frost is ideal in a small blue or pale yellow pot in the shade.

•Beth Gollan is a horticulturalist affiliated with The Planter's Palette, 28W571 Roosevelt Road, Winfield, IL 60190. Call (630) 293-1040 or visit planterspalette.com.