Clematis is the name of a species of flowering vine common to almost any temperate climate. Its flowers are large and often described as "showy." Beyond aesthetics, you might want to prune your clematis vine to remove dead or diseased shoots and to encourage flower growth in the next season. There are three major types of clematis, and each should be trimmed at a certain time. Clematis that blooms in June, and varieties that are late-blooming should be pruned in February or March. Prune early-blooming clematis as soon as they finish flowering in April or May.