While flowering ground covers and shrubs help to dress up areas along sidewalks and near foundations, vines provide vertical eye appeal in the landscape. Often called the queen of the climbers, clematis is one type of vine that can grow in either sunny or slightly shady locations near trellises, fences and arbors. Improper pruning can affect this vine’s ability to blossom.
Clematis is a member of the Ranunculaceae family, also called the buttercup family. While you can encourage clematis to climb up a specific structure, they readily spread and latch on to any surface that provides support, such as nearby rose and lilac shrubs, as well as deciduous trees and evergreens. The vines often grow between 15 and 30 feet long.
Clematis blossoms range in shape depending on the specific cultivar. They often resemble stars or bells. The flowers measure between 2 and 6 inches across and appear in shades of blue, pink, red and white. Many varieties of clematis bloom during the late spring and early summer, while others, known as late-bloomers, produce their blossoms during the latter part of summer. Pruning at the wrong time can restrict blossom formation, leaving you with a green vine, but no flowers.
These perennial vines require regular pruning to remove old, dead growth and overgrown portions. Clematis plants fall into three distinct categories that help define their pruning requirements. One category includes species that bloom on the previous season’s growth, another category includes plants that only bloom on the current season’s growth and the third category includes those that produce flowers on both old and new growth. Pruning during the dormant season can restrict blossom formation on plants that only produce flowers on old wood. These varieties of clematis include Constance, Pamela Jackman, Lagoon and Elizabeth.
While pruning at the incorrect time won’t kill your clematis, it can keep it from blooming for an entire year since the new growth won’t produce flowers until the following year. Ensure the best chance of blossoming by pruning lightly right after the flowers begin to fade. For varieties that flower on new wood, the best time to prune is during the dormant season, but pruning them after the blossom season won’t affect their growth.