Pruning clematis is an important part of maintaining healthy, vigorous plants, but pruning clematis in the wrong way can reduce flowering. One of the best tips for pruning clematis is to determine the type or variety. When to prune and how much to prune varies depending on growth characteristics. An important pruning tip is to use sharp pruning shears and to disinfect your tools after use to avoid spreading diseases between plants.
There are three categories of clematis that determine when to prune. These include varieties that bloom in early spring, hybrid varieties with large flowers that tend to bloom in late spring and summer and late-blooming varieties that don't start blooming until early to mid-summer but continue to produce flowers into fall. Early blooming and mid-season-blooming hybrid varieties flower on wood that was produced in the previous year. The late-blooming varieties produce buds and flowers on wood that developed during the current growing season.
Early flowering clematis varieties bloom on wood that was produced the previous year. Pruning clematis at the wrong time can remove the wood that will support that season's flowers. One of the best tips when pruning early blooming clematis varieties is to wait until the blooming period is over. After the flowers fade, the clematis can be cut back to the desired height and shape and to prevent it from becoming "leggy" or scraggly. It is important to prune these types of clematis no later than the middle of the summer.
With large-flowered hybrid clematis varieties, the best time to prune is in late winter and early spring, when the first buds start to form on the bare wood. The clematis can be shaped by cutting back the tips of the branches right above the developing buds. Every bud that gets removed will result in fewer flowers, so to encourage the most blooms, take off only the wood above the top bud that forms on each branch.
The best time to prune late-flowering clematis varieties is in late winter or early spring, before the new growth starts. These vines flower on stalks that develop early in the growing season, so pruning before growth starts doesn't effect flowering later in the season. Each branch can be cut back to the desired shape and size, usually about 1 to 3 feet (about 30 to 90 cm) from the stalk.
When pruning clematis, clean sharp tools are important. Tools can be cleaned with a 50/50 bleach solution or rubbing alcohol before and after each pruning session. Sharp tools make clean cuts, diminishing the possibility of damage and disease to the plant. Dead branches, diseased wood and broken stalks should be pruned as soon as they are noticed.