Late-blooming clematis vines flower on new wood each year. These perennial vines need yearly pruning to abundantly bloom. When late-blooming clematis is left unpruned, flowering declines, and eventually the blossoms only form on the tips of the vine. These clematis are some of the easiest to prune, as there is no worry of pruning away the following year’s flower buds.
Since the plant doesn’t form new flower buds until after new growth resumes in spring, there is a long window of time to prune clematis. Prune them in fall as soon as flowering completes, but in areas with severe cold, the crown of the vines may be damaged if the old vines aren’t present to provide some cold protection. Late winter and early spring pruning works well in all climates, but the pruning must be done before new growth begins otherwise you end up pruning out the new flower buds.
Standard handheld pruning shears work well for clematis pruning. Bypass shears, which have two sharpened blades and work similar to scissors, cutting through the woody growth without crushing the stem. Keep the shears sharp so they make clean cuts without causing breakage, as clematis vines are brittle. A small handheld pruning saw may be necessary to cut through thick tangles of vines, especially if the clematis has overgrown its trellis or support.
Prune clematis from the bottom up. Cut each vine so it’s no taller than 15 to 30 inches, making each cut ¼-inch above a pair of buds. You may be removing up to 8 feet of growth, but clematis quickly regains its height once growth resumes in spring. Trim any lateral vines or sides shoots from the remaining main vines if they are damaged or rubbing against once another. Always dispose of or compost the removed plant material, as it can harbor insects and disease if left in the bed.