Gardeners growing clematis are often confused about when to prune this climbing perennial. The good news is that if you make a mistake, you will not do irreparable harm---the blooms will simply appear later than usual. Determine whether your clematis falls into Group 1, 2 or 3 and then prune accordingly to encourage vigorous growth and lots of beautiful blooms.
Remove all dead and damaged vines in the spring prior to the start of the growing season. This early spring pruning benefits clematis plants of all types.
Determine which type of clematis you are growing. Some clematis plants bloom in early spring (Group 1). Some bloom in early summer (Group 2). Others bloom during the summer and into the autumn (Group 3). Proceed with the pruning directions for the group your clematis belongs to.
Prune a Group 1 clematis immediately after it finishes blooming in the spring. Remove the spent blossoms just below the blooms. Group 1 clematis plants require only minimal pruning to shape them and keep them growing attractively.
Trim Group 2 clematis plants in the spring by cutting each vine back to the first set of green buds. This will remove approximately one-third of the stem length. To help the plant develop a strong root system, cut back the entire plant to 1 foot in height for the first two growing seasons after planting.
Prune Group 3 clematis plants in the early spring by cutting each stem down to approximately 1 foot in height.