Clematis are vines grown for their eye-catching flowers. They come in single and double forms, in a wide range of colors. Blooms appear spring through fall, depending on the species.
Some clematis have crinkled blooms.
Clematis belongs to a diverse group of mostly woody deciduous vines. According to Reiman Gardens, at Iowa State University Extension, there are more than 250 species and 5,000 existing cultivars.
Clematis vary in height from small plants that grow just 2 to 5 feet, to vines that reach 30 feet, according to the Clemson University Cooperative Extension. Flower forms range from small clusters and bell-shaped varieties of species clematis to the familiar large, open blooms of hybrids. Flower hues include white, pink, purple, red and yellow. Species clematis tend to be one color, but some hybrids come in color combinations.
Growers divide clematis into three main groups, according to Reiman Gardens. Early flowering clematis bloom from April through June from buds formed the prior season. Examples include C. alpina and C. macropetala. The second category are clematis that bloom twice, such as ‘Ramona’ and ‘The President.’ This group flowers in May or June from last year’s growth, and again in late summer on current season growth. The third group of clematis bloom on current season growth from late May to September. ‘Ernest Markham’ and ‘Hagley Hybrid’ are in this category.