Growing clematis: beauty that comes easy

Susan Austin is a one-woman antidefamation league for clematis.

The flowering vine, she says, has gotten a bad rap as being finicky and hard to grow, a claim she dismisses. This feisty nurserywoman is also determined to rescue clematis from its typical spot in gardens: climbing a lamppost or plastic trellis.

"If I see one more clematis growing on a fan-shaped trellis, I'll burn it down," she says with mock severity.

Ms. Austin (no relation to the writer) has earned the right to voice such strong opinions. Since 1984, she has owned the Completely Clematis Specialty Nursery in Ipswich, Mass., and is considered by expert gardeners to be the doyenne of clematis (pronounced CLEM-ah-tiss) on the East Coast.

Her nursery is a slightly ramshackle affair that she runs from her home.

As you pull into the driveway, two mischievous Pembroke corgis, Willy and Grendel, greet you before whipping off to explore the yard. Two small greenhouses shelter hundreds of gallon pots of clematis, all neatly labeled. It's still early yet, and only the Alpina varieties are blooming. The rest are coming out of dormancy, dreaming of summer sun.

Inside the house are stacks of pots and piles of gardening magazines. The cat, Litski (dubbed CEO of rodent control), dozes on the kitchen table. The tiny office is dominated by a fax machine that churns out orders to be filled by Austin's two-person staff.

Each year, more gardeners discover the charms of clematis. As a climber, it's unbeatable. And, unlike wisteria and honeysuckle, it won't harm the structures on which it climbs, whether tree, fence, or house.

There are a huge variety of species (about 230) that come under the genus Clematis, and most are fast growers, eager climbers (with some support), and prolific bloomers.

The flowers tend to be real jaw-droppers, which, depending on the type, come in luscious shades of pink, purple, blue-violet, yellow, red, burgundy, cream, and white. The blossom shape and size vary greatly; many have an exotic, tropical look, reminiscent of passionflowers or orchids. Most have a profusion of blossoms, which, as the season progresses, turn into attractive, whorled seedheads that add interest to the autumn and winter landscape.

Austin says American gardeners have shied away from clematis because of misperceptions about their care.

"People should do the same kind of research before buying a clematis as they do when shopping for a rose or shrub," she says. Many gardeners buy a plant simply for the flowers, ignoring information about height and pruning.

The result can be a 20-foot tangle of foliage and blooms near the top, with the lower half bare. This scraggly appearance is what turns people off clematis, but it's entirely unnecessary, Austin says.

By choosing a plant that will grow to the right height for its intended location, and brandishing the pruning shears when needed, gardeners will be rewarded by a full, compact, and gorgeous clematis.

People who are intimidated by pruning should instead choose a variety that doesn't need it, such as montana Wilsonii or General Sikorski.

Clematis are sold as two- to four-year-old plants. Many a gardener has lost a new clematis by planting it directly from its nursery pot into the cold ground in early spring. Whatever time of year you buy, Austin recommends that young plants be kept in containers for two months so the root system can develop.

Another common mistake is to assume that, because new plants look small and fragile, they can be treated like just another perennial. Austin suggests thinking of them as shrubs that will live 50 years or more, and prepare the planting hole with posterity in mind.

Clematis is bothered by few insect pests, but the large-flowered varieties are susceptible to a fungus called clematis wilt. The fungus attacks through an opening in the stem and causes the entire plant to wilt. It rarely kills the clematis, especially one that has been planted deeply. (See accompanying story.)

Most clematis flower best in full sun, although there are several varieties that will bloom in shade. For gardeners without enough sun to grow roses, such clematis as Silver Moon, Royal Velvet, and Rouge Cardinal are a boon in shady spots.

For beginners, Austin recommends the small-flowered varieties, which she calls "unkillable." Good choices include: Betty Corning and Sweet Autumn.

Most gardeners place clematis where its spectacular flowers can be appreciated - such as fences and rock walls. And there's nothing wrong with the ubiquitous lamppost or trellis, despite Austin's protestations. Bear in mind a clematis that grows to 30 feet will never look right on an 8-foot lamppost.

Austin prefers to see clematis grown in a more naturalistic fashion, such as scampering over a large tree stump or spreading horizontally, like a ground cover. She loves the idea of clematis twining majestically through the branches of a shrub or tree. She realizes, however, that suburban gardeners who like tidy beds may resist such an approach.

Austin shrugs philosophically. If she can make converts out of even a few gardeners, her job is done.

"Clematis are easy to grow," she says, "otherwise I wouldn't be in the business."

Tips on cultivation

No matter where you live, or when you buy your clematis, repot it into a bigger container and let it "fatten up" for two months. Feed with a liquid fertilizer such as Rapid Grow.

When the plant is ready to graduate to the yard, choose a sunny site that is not overly exposed to wind. Set up a trellis or plastic-coated wire for climbing support, if desired.

Dig a 24 by 24-inch hole if possible - and amend the soil with a mixture of compost and well-rotted manure.

Add a handful of 5-10-10 fertilizer and superphosphate to the planting hole. Thereafter, a liquid fertilizer such as a fish emulsion can be applied every month during the growing season.

Plant clematis so the crown (where the stem joins the roots) is 3 to 4 inches deep (and as much as 5 inches if the soil is sandy).

Water once a week until the plant is established.

Shade soil at the roots by mulching, or grow shallow-rooted plants such as veronica or dianthus at the foot of clematis.

Pinch the plant back the first year to encourage bushy growth.