Clematis is a member of the Ranunculaceae family. In the 1850s plants from Japan and China were imported and used for parentage in the breeding programs. Most of the clematis breeding and hybridizing was concentrated in England, Belgium and Germany. Clematis are enjoying renewed popularity, especially the small-flowered types that are very hardy and disease-resistant.
Most are woody deciduous climbing plants, there are a few evergreen and herbaceous varieties. Leaves are opposite on the stem with three to five leaflets. The plant supports itself by twining its leaf stalk around a support or other plant. The flowers have four to eight petal-like sepals in numerous colors and shades and the dried seedpods are wonderful in arrangements. Hybrids provide large flashy colored blooms through out the summer. The species often have fragrant blooms and are very hardy and disease resistant.
There are three general flower forms:
1. Small flowers in panicles and irregular spreading clusters.
2. Bell or urn-shaped flowers.
3. Large flat open flowers.
Clematis need at least 6 hours of direct sun a day. Light dappling from over head leaves during mid day is helpful to prevent fading of some large flowered varieties. Eastern exposures are a good location. Air circulation is very important to keep the plants from getting mildew and other fungal diseases. Plant clematis in an open location with rich well drained soil and a neutral pH. Prepare the soil to a depth of 24 inches in an area approximately three feet wide mix in compost or rotted manure and some coarse sand. Cultivate the area thoroughly and mix in some green sand and rock phosphate. When planting cut stems back to 12 inches. This will help the plant branch as it begins to grow and reduce the chance of stems breaking during planting. Some support should be provided for vines unless you want them to scramble over walls, small trees or shrubs. Use galvanized or plastic coated wire to train your vines on a wall or fence. Fasten this to the wall with eyebolts four inches from the wall allowing air to circulate between the wall and vine and room for the vine to twine. Pergolas are suitable for the larger, more vigorous types of clematis.
Clematis like their faces in the sun and their feet in the shade. Use shallow rooted ground covers to create a cool root environment. Hardy geraniums, creeping phlox, coralbells, lamium or Alchamilla would look lovely. You should give your vines a light pruning every year. When you prune them depends on when they flower and whether they flower on old wood or new growth. Below are the three general types and the best times to prune.
Type A: Early-flowering Clematis
These bloom in early spring, generally April and May from buds produced the previous season. Prune them back after they bloom before the end of July. This will allow time for new growth to set flower buds for the next season. Be careful not to cut into woody trunks.
Type B: Large-flowered Hybrids
Large-flowered hybrids bloom in mid-June on short stems from the previous season’s growth and often again in late summer on new growth. Prune in February or March by removing dead and weak stems. Plants in this group have the tendency to become bare at the base as they mature. Use a taller ground cover or shallow rooted perennial to help conceal the stems.
Type C: Late-flowering Clematis
Plants in this group flower on the last two to three feet of the current season’s growth. Some types begin blooming in mid-June and continue into the fall. This is the easiest group to prune because you don’t need to maintain the old wood. February or March is a good time to cut each stem to a height of about two to three feet.
Species
Clematis alpina - 6 to 8 feet in height, blooms April-May. Flowers on long stalks, 1.5 inches nodding, bell-shaped flowers, lavender or purple-blue in color. Seed heads are gray fluffy balls holding until winter. Hardy, foolproof plant. Type A pruning.
Clematis armandii - 15 to 30 feet in height, blooms April-May. Two-inch diameter blooms, creamy white in large axillary clusters; has a strong vanilla scent in warm weather. Strong, vigorous grower. Type A pruning; can cut to base to rejuvenate vine.
Clematis flammula - 15 to 20 feet in height, blooms August-September. Flowers occur in terminal clusters in great masses; are 1 to 1.5 inches in diameter, white. Grown from seed so growth can be variable. Type C pruning.
Clematis macropetala - To 15 feet in height, blooms April-May. Flowers are double, nodding bells, 2.5 to 3 inches in diameter, pale blue with purple shading. Seed heads last into winter. Foliage is neat and attractive; plants prefer cooler, shady location. ‘Snowbird’ is pure white with a hint of green on inside of bloom. Type A pruning.
Clematis viticella - 10 to 12 feet in height, blooms July-September. Flowers slightly nod, are 1.5 to 2.5 inches borne singly or in clusters on a slender stalk; rich deep purple with small green stamens. Vigorous and easy to grow. Type C pruning.
Hybrids
Comtesse de Bouchard - 6 to 8 feet in height, flowers July-August. Easy to grow and a prolific bloomer this is a good plant for smaller spaces. Flowers are 4 to 6 inches in diameter, pink with creamy stamens. Type C.
Marie Boisselot - 8 to 12 feet in height, flowers June-September. Opening flower buds are flushed with lilac-pink flowers are 8 inches in diameter, white with creamy stamens. Type B pruning.
John Warren Clematis Mrs. Cholmondeley - 20 feet in height, flowers May-October. This is a foolproof variety. Blooms are light lavender blue, paler along the midrib, filaments white and anthers brown. Type B and C pruning.
Niobe - 8 feet in height, flowers June-September. Cup shaped bloom opens dark ruby-red then turns to bright ruby red with cream stamen. First flowers are 6 inches in diameter, later ones 4 inches in diameter. Moderate grower with some bloom throughout the season. Type B and C pruning. Vyvyan Pennell -8 feet in height. Flowers June and September. Flowers are 6 to 8 inches in diameter, double at first, single later. Deep violet-blue blooms suffused with purple-red golden stamens. Type B pruning.