Mary Snoddy

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Clematis - Showy Vine for Trellis, Container, Groundcover

Clematis (pronounced  CLEM-ah-tiss) is a popular flowering vine. There are many species and hundreds of cultivars, with new hybrid introductions coming to nurseries every year. Most are deciduous but fragrant Clematis armandii is evergreen. Most have large, showy, colorful, flat , single or double flowers. A few have hanging bell-shaped flowers, while others have strap-like petals. Try to purchase a new vine while it is in bloom to confirm the color. The label will likely provide pruning recommendations appropriate for that variety.

Clematis tolerates a variety of soil types but prefers a moist, alkaline soil, so be prepared for a light application of lime every fall if you garden in an acid-soil location. They are weak climbers and will look best when secured to a trellis with soft twine. They can also be grown in containers or allowed to scramble along atop the soil.

Clematis cultivars vary in mature size. Typical size is six to twelve feet, with a few extending to thirty feet or more. There are three main classes of Clematis.. Type dictates the pruning method. Type I vines flower in early spring on wood produced in the prior year. They should be pruned immediately after flowering to spur new growth for next year’s flowers. Type II are repeat bloomers that flower on both old and new wood. Cut out dead wood in spring, deadhead throughout the season, then prune again after most flowering has subsided. Type II can be pruned drastically if vines have become overgrown. Type III vines flower later than the first two groups, in late summer and fall. They bloom on both new growth and old growth. Pruning is optional for this group, but vines will be much more attractive if they are pruned down to 12-15 inches in early spring.

Clematis like to grow with “their heads in the sun and their feet in the shade,” which sounds daunting but can be accomplished with a thoughtfully placed large rock, gravel, container, or groundcover plant. Best flowering occurs with at least half-day sun. In the deep South, protect plants from scorching afternoon sun to prevent crispy leaves and faded flowers.

Two of the most widely grown Clematis are ‘Jackmaii’ (vigorous grower with large, flat purple flowers) and ‘Henryi’ (large, flat, pure white flowers). ‘Rooguchi’ has a downward-facing purple bell-shaped flower. Though it is not as eye-catching as the flat-flower types, it is popular because it reblooms freely over several months. Seed heads are interesting pinwheel tufts of fuzzy threads.

 All parts of Clematis are toxic to humans and animals.

Purple ‘Jackmanii’ is one of the most popular varieties of Clematis.

Clematis seeds look like fluffy pinwheels.