A. Clematis fall into three categories-those that bloom on new wood (usually from late June on), those that bloom on old wood (from July to fall) and those that are blooming on old and new wood (in spring and again in late summer). For pruning purposes varieties that bloom on new wood can be cut back hard, to allow for production of new blooming growth. Don't do much pruning on varieties that are flowering on old wood, except to remove wood that is dead or spindly. The same is true for those types that bloom twice, only prune to shape or to remove dead branches. If you're not sure what varieties you have, wait until they bloom-the timing should be a good clue.