Group 1 - Certain species clematis and their cultivars which bloom early in the year. Some of the more commonly found representatives of this group include the Montanas. All of the Group 1 clematis bloom on growth made the previous year. They can be pruned to keep them within their allotted space, or to remove dead and unsightly foliage. Note however, if they are pruned late in the season, or before they flower in the year, you will be cutting off potential flower buds. They should be pruned right after flowering, if at all.

 Group 2 - These are the large flowered hybrids. All of the clematis in Group 2 bloom on 'old wood' (actually on short shoots from old wood) and should not be pruned except for deadwood pruning in early spring after the leaf buds open slightly. The number of later flowers can be increased if the seed heads from the first flowering are removed right after the blooms drop their tepals.

 Group 3 - Clematis in Group 3 mainly flower on new wood produced in the current year and should be pruned back severely every year in late winter, when they are completely dormant, to about 12 - 14 inches. Leave at least two pairs of buds (4) on each stem of the plant. Most Group 3s are very fast growing and will reach their full height before blooming every summer. If you fail to prune these, they will develop long 'legs' that get woody and will be devoid of foliage and blooms.