By Dr. Leonard Perry, Extension Professor
University of Vermont
Are you looking for a plant that can grow up a trellis or fence, serve as an interesting ground cover, or perform well as a container plant? If so, then the plant you want is the clematis.
This versatile and hardy flowering vine comes in a variety of colors ranging from deep purple to shades of blue, mauve, pink, red, yellow, cream, white, and bi-colors. Flower size, depending on variety, can be as small as one-fourth inch up to nine or ten inches in diameter. Some varieties--there are more than 250--are best suited for shade, others for full sun, meaning you can probably find a clematis for every growing situation. In Vermont, clematis generally does best in full sun.
Clematis hybrids can be divided into 11 groups. Some flower later in the summer on current season's growth like 'Ernst Markham' (red with gold stamens; okay to prune in early spring). Others flower earlier in season on last year's growth like 'Duchess of Edinburgh' (pruning in spring will cut these flower buds off, so prune back only after bloom).
The most popular are the large flowering varieties, which were first introduced in the mid-19th century. 'Jackmanii,' with its showy purple flowers, became popular in England in 1863. 'Elsa Spath' is another prolific bloomer, producing lots of lovely blue-purple flowers. If you like pink, try the classic 'Nellie Moser' with flowers five to six inches across.
A favorite white variety is 'Duchess of Edinburgh' with early semi-double flowers with yellow stamens. For bi-colors, try 'Lincoln Star.' It sports eight-inch raspberry red flowers with white edges.
Planting several different varieties almost guarantees you a continuous sweep of color from spring to the first hard frost. Most varieties do well in hardiness zone 3 and up, but talk to your local garden center experts for recommendations on variety selection.
Although you can plant clematis almost any month you are able to work the soil, spring and early autumn are the best times to plant. Dig the soil about 18 inches deep, working in several scoops of compost. Water in a liquid fertilizer according to the label directions. You should plant your clematis one to two inches deeper than it was in the pot, burying one set of leaves below the soil level.
Water thoroughly, then add mulch around the base of the plant to keep
the roots cool and conserve moisture. Staking may be needed if you want
to train the clematis to grow up a trellis though obviously would not be
required for plants you plan to let sprawl on the ground or grow through
low-growing shrubs and hedges. For a fence post, use fishing line to train
the vines to wind around the post.
Although clematis is attractive as a landscape plant, it also makes an excellent cut flower. When cutting clematis for arranging, choose flowers with strong, thick stems. Remove foliage to reduce transpiration, and place in cold water immediately. Blossoms need to be conditioned overnight before arranging.
Clematis plants can be found at many nurseries, greenhouses, and garden
centers, or ordered though on-line catalogs. With proper planting, early
care, and patience, they will continue to prosper for years to come. So,
why not plant some today. Their place in your landscape is only limited
by your imagination.