A member of the buttercup (Ranunculaceae) family, clematis perennials are hardy and long lived, surviving as long as 25 years. The word is derived from the Greek word meaning vine, which should come as no surprise. All need to be staked. There are both deciduous and evergreen clematis, but all prefer well drained soil and generous sunlight.

There are about 250 species of clematis perennials, and numerous garden hybrids, all of which have a reputation of being difficult to grow (not necessarily justified). Soil should be pH neutral, rich, and, as noted, adequately loamy. Their roots do not compete well with tree roots and want a moist, cool environment.

Varieties of Clematis Perennials

Clematis can be grouped into three categories--the early and the late bloomers, and the large-flowered hybrids. Most of the small-flowered species blooming from April through May grow to about 30 feet. Those include C. alpina with bell-shaped blue or lavender bell-shaped flowers and C. macropetalia with double nodding bells two to three inches in diameter colored blue to purple.

Among the species of clematis perennials that bloom toward the end of the season are C. viticella with deep purple flowers growing only to about 12 feet, and C. maximowicziana a vigorous grower with white flowers that grows as long as 30 feet. The showy hybrids, however, are very popular. Well known among these are Mrs. Cholmondeley, said to be foolproof. This grows to about 20 feet and produces pale lavender blooms from May through September. Earnest Markham grows only 10 feet and produces deep magenta flowers in midsummer.