When and how should I prune my clematis?
That depends on when it flowers. Spring-flowering clematis bloom on last season's growth. Wait until after it blooms to prune. Remove dead and damaged stems and prune back remaining stems to reduce the size of your plant.
Late-spring flowering clematis bloom on shoots produced on old growth. Remove dead and damaged stems before growth begins. Trim remaining stems back to healthy buds. This is the framework for the flowering shoots.
Summer- and fall-blooming clematis bloom on new growth and can be pruned anytime during the dormant seeason. Cut these plants back to 6 to 12 inches above ground level.