Clematis is a member of the buttercup family. There are over 250 species of Clematis, as well as a number of hybrids. Clematis includes a wide variety of flower forms, foliage, color and plant height. Leaves are usually compound with three to five leaflets opposite each other on the stem. These beautiful plants depend on the leaf stalk for support.
History of Clematis
Clematis plants that were exported from China and Japan were crossed and improved during the 1850s. There was much cross propagating done in Belgium, Britain, France and Germany at that time and through the remainder of the 19th century. Today, the Clematis we grow in our gardens are very hearty and disease resistant.
Where to Plant Clematis
Many gardeners avoid Clematis because they have a reputation for being hard to grow. If the plants are planted in an area that fits their needs, they flourish. Most Clematis prefer full sun, which means they need six or more hours of sunlight daily. Plants of blue and red flowering hybrids may fade in full sun. Plant these varieties in an eastern location or in partial shade.
Clematis should always be planted in an area where air can move easily around the plant. Rich soil with a neutral PH – 7.1 – should be used. Though Clematis foliage and stems prefer full sun, the roots enjoy an environment that is cool and moist. Most Clematis do not grow well if they have to compete with large tree roots.
All Clematis should be supported by a trellis, wall or stake in order to allow them to climb. Plants that creep along the ground do not flourish, but they will grow around unsightly stumps in your yard for a more “wild” look.
Soil for Growing Clematis Vines
Always check soil before planting Clematis to ensure the PH level is correct for the plant’s needs. PH level will be marked on the plant’s packaging.
Prepare an area three feet in diameter and 24 inches deep. Add compost or well-rotted manure. This helps with drainage and aeration.
Planting Clematis Plants
Once the soil is prepared and the appropriate sized hole is dug, cut the Clematis stems to 12 inches in height. This will reduce breakage of stems during the planting process and allow the Clematis to branch out as it grows.
Be sure the crown of the plant is between one and two inches below the ground surface. Fill the hole with soil, firm to prevent air pockets and water deeply.
Planting Bare Root Clematis
If you are planting bare Clematis roots, soak them in water for an hour before planting. This allows the roots to become fully hydrated. When the plant is securely in the soil, cover with fine wire, such as chicken wire, to protect against animals and lawn equipment.
Clematis roots enjoy being cool and moist, as mentioned earlier. In order to maintain this environment, under plant with perennials or a ground cover that has a non-invasive root system. Suggestions include grape hyacinths, coral bells, candytuft and creeping phlox.
A two inch layer of mulch can be substituted for under planting.
Fertilizer for Clematis Plants
The first season, Clematis may only experience a small amount of growth and will only produce a few blooms, if any. This is the time when roots need to become well established. Fertilize only once during the first growing season.
Once Clematis roots have become well established it may not need to be fertilized. Be sure Clematis receives at least one inch of water every week during the growing season.
Trellis Support for Clematis Vines
Clematis need support. This can be a trellis or other type of frame. The plants also do well when left to climb on walls or stumps. Be sure the trestle is made up of thin material and that it is not heavy. Petioles will not cling to thick material.
Galvanized or plastic wire works great. It should be fastened to a wall and be large enough to support the Clematis when it matures. Wire allows good air flow, which promotes growth and blooming. A pole can easily support small varieties of Clematis. Larger plants do well on arbors and pergolas.
Annual Care of Clematis Plants and Vines
When Clematis is well established be certain to water deeply every week. During a heat wave/drought, you may have to water every three to four days. The secret of Clematis to is to keep the roots cool and moist.
In spring, add a new layer of mulch to a depth of two inches if you haven’t under planted. Rocks may be placed around the Clematis to cover the roots, which ensures water retention.
Transplanting Clematis Plants
The best time to transplant Clematis is in the fall or very early spring. Clematis must be transplanted before growth begins. Before digging up the plant, be sure the soil is moist. Then, dig up a large section of the root. Before relocating, be sure the new area meets all requirements as stated earlier in this article.
Pruning Clematis Vines
In order to promote optimum blooms, Clematis needs to be pruned annually. If plants are not pruned, they will still flower, but not in selected areas. Blooms may appear high on the plant.
The earliest blooming Clematis must be pruned early in the spring before any growth appears. Later blooming varieties must have new growth before being pruned.
Some types of Clematis may cross lines between the two. Check package instructions. If vines are tangled, cut dead wood from between them and spread and train as desired. This enables the blooms to cover a larger area and not bloom in clumps.
If you wish to propagate Clematis, take cuttings in May or June. These should be taken from partially hardened shoots and from growth of the current year. Plant Clematis in one part peat and two parts sand. Use a growing compound to speed the rooting process. Be sure the new cutting has high humidity, lots of light and that it’s kept warm.
If special care is taken, cuttings should root in a month to six weeks. Large flowered hybrids can take up to 12 weeks to root. If roots haven’t taken hold by late August, Clematis should be planted in pots and wintered indoors. Plant these early in the spring.
This is an easier method of propagating Clematis. Choose a stem from last year’s growth, or a mature stem from the current season. Plant it in equal parts of peat and sand at the nodes. Rooting will take place within a year. Detach the rooted sections and plant according to site requirements.
Clematis Problems and Disease
The biggest problem you are likely to experience with Clematis is fungal stem rot. Leaf spot is also caused by fungus and is often referred to as wilt. This disease is more common in hybrids that produce large blooms. Small blooming hybrids are less susceptible to wilt. Symptoms are sudden stem collapse that appears when buds are ripe to open. Within two to three days, the leaves and stem will turn black.
Wilt can attack any part of Clematis, including the area below the soil. Remove the wilted section of the plant. Clematis will recover from wilt and grow from buds located lower on the plant.
In July and August, watch for a powder-like mildew that appears on flowers and new stems. Treat mildew with an environmentally friendly fungicide when it first appears. If left, mildew fungus will strike leaves and buds and the Clematis won’t flower. Mildew is caused when plants aren’t properly ventilated. Be sure air can circulate around the entire Clematis plant.
Clematis can become infested with aphids that feed on the succulent juices of new growth. Slugs enjoy feeding on the bark of new stems. Earwigs feast on new blooms and foliage and bore into flower buds. Treat pests with environmentally friendly pesticides.
With a little care, Clematis will bloom year after year. They bring beauty and color into your yard and garden, both with the blossoms and in the form of butterflies and birds.
Want to learn more about Clematis?
Home of Clematis is a comprehensive site devoted to every aspect of growing these wonderful vining plants.
Clematis.org is the official site of the American Clematis Society.
Gardenweb has an active Clematis forum.
Mary M. Alward is a freelance writer living in southern Ontario. Besides writing, Mary enjoys gardening and spending time with her family.