Guide to the Types of Clematis

Clematis is a sun-loving perennial climber.

Clematis have been called "show-stoppers" by Colorado State University Extension horticulturist Margaret Wolf. These climbing vines are diverse, with varieties both woody and herbaceous, deciduous and evergreen. Indeed, the genus Clematis includes some 250 species. The showy blooms can have between four and eight apparent "petals"; Wolf explains that these are actual colored sepals, surrounding the much smaller true flowers.

Early-Blooming Types

Some clematis bloom in the early spring -- April and May. Some early-blooming species include C. alpina, C. armandii, C. chrysocoma, C. macropetala and C. montana and numerous cultivars, including Columbine, Ruby, Blue Bird and Markham's Pink. These early bloomers produce new flowers on buds that were produced the previous year. Ohio State University Extension horticulturist Jane C. Martin recommends pruning these varieties soon after blooming -- no later than late July; this pruning allows adequate bud formation well before the plant goes dormant in fall, ensuring a wealth of blooms the following spring. Avoid pruning the large, woody trunk, however.

Repeat-Blooming Types

Some hybrids produce exceptionally large, impressive flowers in mid-June, followed by a second blooming later in the summer. There are two chief species: C. florida and C. patens, and many cultivars. Martin singles out Nelly Moser, Miss Bateman, Lasurstern, Duchess of Edinburgh and Mrs. Cholmondeley. Others include Alice Fisk, Chalcedony, Crimson King, Daniel Deronda, Empress of India, Fair Rosamond, Fairy Queen, Fireworks, Herbert Johnson, Horn of Plenty, Imperial, Princess of Wales, Silver Moon, Snow Queen, The President, Titania, Twilight, Veronica's Choice and Violet Charm. Prune these by removing dead and weak stems in late winter -- February to early March.

Late-Blooming Types

Some clematis flower from late summer through early fall, producing large blooms on the last few feet of the current season's growth. Late-blooming species include C. flammula, C. x jackmanii, C. maximowicziana, C. tangutica and C. viticella, as well as C. integrifolia, C. orientalis and C. texensis. Hybrids in this category include Aromatica, Blue Boy, Comtesse de Bouchaud, Ernest Markham, Lady Betty Balfour, Margaret Hunt, Pagoda, Pink Fantasy and Victoria. To boost the number of blooms, prune these clematis back to about 2 or 3 feet in February or March; you do not need to retain the previous year's growth.

Evergreen Types

A few species and hybrids of clematis stand out from the others because their leaves stay green all winter. These include C. armandii, popularly known as Armand's clematis, and C. vitalba, commonly known as evergreen clematis or old man's beard. C. vitalba is so robust that it can act in some environments as an invasive weed. Also vigorous, C. armandii can reach 15 to 30 feet tall, and it is limited largely by the height of the support structure.

References

• Colorado State University Extension; Cheerful, Climbing Clematis; Margaret Wolf; July 10, 2010
• Ohio State University Extension Fact Sheet; Growing Clematis; Jane C. Martin
• Echter's Nursery & Garden Center: Pruning Clematis Vines
• Clemson University Cooperative Extension; Evergreen Clematis; Karen Russ; 2009
• U.S. Department of Agriculture Plants Database: Plants Profile for Clematis Vitalba

Resources

• American Clematis Society
• International Clematis Society