Regional Gardening Reports :: National Gardening Association

In the Garden:
Upper South
June, 2007
Regional Report

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A well-grown clematis, such as this 'Blue Belle', can provide weeks of color in the garden.

Growing Up With Clematis

Hopefully, we enjoy most of the plants in our gardens, but there are certain ones that catch our hearts. For me, one of those plants is clematis. (KLEM-a-tis is the correct pronunciation, but I've always said kle-MAH-tis.) No matter how it's pronounced, vining clematis can be stunning when covered in colorful blue, purple, pink, yellow, or white flowers. In my mother's garden, there was the ubiquitous Clematis x jackmanii (introduced in 1862, it is the most popular clematis grown today), placed at the end of the clothesline. However common the clematis or its location, when in bloom, with seemingly hundreds of flowers, my family relished its beauty. Unfortunately, growing clematis has also stymied many a gardener, including a friend of mine who is a great gardener.

Although having a reputation for being difficult to grow, to say nothing of being confusing when it comes to pruning, clematis needn't be either of these. It does pay to do a bit of homework in order to know, understand, and provide the basic needs for whichever clematis you choose. Then consult a list of clematis specially selected for beginners by clematis growers worldwide, such as the one compiled by the International Clematis Society (

Consider the Site
The mantra for growing clematis is "feet in the shade, head in the sun." Over the years, from my own experience with clematis, I've found that a site that gets very light, filtered shade combined with a 2-inch layer of mulch yields the most consistent results. Another option is to underplant with a ground cover or perennials with shallow, noninvasive roots, such as Artemisia 'Silver Mound', hardy geraniums, creeping phlox, coral bells, candytuft, or veronica.

It's also important to have plenty of room around the plant for good air circulation to avoid diseases. The ideal soil is rich in organic matter and well draining, with a pH close to neutral (7.0). I'm lucky to get my new clematis planted "wherever" and "however," but for the best results, prepare a planting hole that's 24 inches deep and 36 inches wide, and incorporate compost or rotted manure one-third by volume. Clematis can survive for 25 to 50 years, so choosing a site and preparing it well will pay off in spades.

It's also important to plant clematis with the crown 1 to 2 inches below the soil surface, as this enables the plants to recover if anything should happen to the aboveground growth. Consider using a protective collar of hardware cloth or chicken wire to fend off rabbits, string trimmers, and so forth. Until plants are well-established, plan on fertilizing in the spring with a fertilizer with a ratio of 3-1-2 or 4-1-2. After that, the choice is up to the gardener.

Among the some 250 species and over 3,000 cultivars, there are clematis that range from floppy perennials growing only several feet tall to aggressive vines reaching 20 feet or more. As you choose and site your clematis, consider it's ultimate size. Don't expect one that maxes out at 4 or 5 feet to ramble over the garden shed. These shorter-growing ones, -- usually large-flowered hybrids -- are ideal for surrounding mailboxes and lampposts as well as in containers. Clematis climb by means of the leaf stem curling around a support, so thin supports like wire or string are usually best. Often, these are combined with sturdier structures, such as wooden arbors or pergolas. The English like to let clematis clamber upward through shrubs and trees.

Trimming clematis correctly each year leads to the greatest number of flowers. Although there are exceptions, generally a clematis is divided into one of three pruning methods, based on when it blooms.
1. Group 1 or A are the early-flowering types that bloom on growth from the previous season. Prune these immediately after blooming to shape or tidy up.
2. Group 2 or B are the large-flowered hybrids that bloom in early summer on the previous season's growth and again in late summer on new growth. Prune these in late winter or early spring only to shape or remove dead or weak stems.
3. Group 3 or C are the types that flower on the current season's growth. In late winter or early spring, cut these back to 1 or 2 feet.

If you want more information on pruning or are unsure which category your clematis falls into, consult a source such as Clematis on the Web (

Other Tips
1. Clematis need the equivalent of 1 inch of water each week during the growing season.
2. Clematis can be transplanted in the fall, late winter, or early spring before growth begins.
3. If beginning with small plants, transplant to gallon pots for the summer, then plant into the garden in the fall.
4. Propagate clematis by cuttings or layering.
5. The main problem with clematis is a fungal stem rot and leaf spot called clematis wilt. Remove the diseased stem below the wilted section.
6. For fragrance, consider the sweet autumn clematis (C. ternifolia) or one of the C. montana forms.
7. Clematis make great cut flowers.

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