Clematis (Clematis spp.) is a perennial vine that includes 250 species and many hybrid varieties. Clematis are hardy to USDA hardiness zone 3 and can live for up to 25 years. Leaves sit opposite on stems, which twine into tendrils that give the vine support on trellises and other structures. Flowers are large, vivid in color and come in several shapes and configurations. Clematis needs only a minimum of care to produce healthy, abundant blooms.
Clematis varieties come in many different colors, shapes and growth habits. Early blooming varieties will flower in April or May. This group includes Clematis Montana, Clematis chrysocoma, Clematis macropetala and Clematis armandii. Late blooming varieties include Clematis jackmanii, Clematis viticella, Clematis tangutica and Clematis maximowicziana. Some of these begin blooming in mid-June and continue into the fall, according to Ohio State University horticulturist Jane C. Martin.
Plant clematis in an area where it will get at least six hours of sunlight each day. Clematis prefers a soil pH of 6 to 7.5, according to Bachman’s. If your soil is very acidic, work in some garden lime to raise the pH number. Adding humus to the soil will aid air circulation and water retention in the soil. Dig a hole slightly larger than the root ball. Examine the plant carefully and make note of where the pairs of buds emerge from the stem. Plant the clematis so that at least one or two buds are above the soil level. Water generously and spread 1 to 2 inches of organic mulch, like wood chips or dried leaves, to keep the roots cool and prevent weed growth. Set in a trellis or other supporting structure so that the plant can grasp onto it as it grows.
Clematis roots run deep, so water thoroughly during dry periods. Tie vines gently to supports to prevent breakage. Fertilize plants with 5-10-10 fertilizer when you see 2 inches of new growth in the spring. Alternate this with 10-10-10 every four to six weeks. Protect vine roots over the winter months with a thick layer of mulch.
Pruning helps to control the growth and produce more abundant flowers. Remove dead or damaged stems at any time. The type of blooming pattern determines how to prune the vines. Group I grows on old wood and only requires pruning after blooming to control size. Group II bloom on old wood and then on new stems. In early spring, prune the vines lightly to remove the weak stems and promote growth. Group III types flower only on new growth. Cut these vines back to 12 inches early in the spring, according to WhiteFlowerFarm. Observe your plant’s growth pattern to determine how to prune the vines.