How to Prune Clematis: Groups 1, 2 and 3 Explained

Prune clematis by group, not by calendar: Group 1 right after it flowers, Group 2 lightly in early spring and again after the first flush, and Group 3 hard in early spring. Illinois Extension says the group refers to whether the plant blooms on new wood, old wood or both, and that this affects both flowering and pruning technique. Cut the wrong group at the wrong time and you remove the wood that was about to flower. This guide sits under our clematis care guide, which covers sun, planting depth and wilt.

The three pruning groups

The sources vary on how hard to cut Group 3. UVM says a foot above the ground in late winter, and Clemson says about 2 to 3 feet in February or March. Ohio State adds that Group 3 can be pruned in very early spring or even in late fall after blooming.

How to tell which group you have

1. Check the plant tag or the variety name. Illinois Extension says the group depends on whether the plant blooms on new wood, old wood or both, so the label or cultivar name usually settles it.
2. Match the bloom time to a group. Early spring bloom points to Group 1, a late spring flush then more flowers later points to Group 2, and flowers only from late summer into fall point to Group 3.
3. Apply the old-wood, new-wood rule. Ohio State’s rule of thumb: if a plant blooms on old wood, prune after blooming; if it blooms on new wood, prune in early spring before new growth begins.

If you cannot tell

Kansas State’s fallback is to cut all stems back to the ground or to new growth. The cost is shorter plants, a few less flowers and a slightly later bloom, so it is a safe reset rather than a way to get the best display. Colorado State describes the same approach: work through the vine until each stem is pruned back to new growth, or to the ground if the shoot is dead.

Group 1: after flowering

Ohio State and Mississippi State both say Group 1 should be pruned after it flowers, because it carries its flower buds on last year’s wood. Illinois Extension says to prune after bloom only if needed to reduce size, control growth or make the plant fuller, and to remove only dead wood in spring. A spring cut before flowering takes off the buds this group has already formed.

Group 2: two light passes

Illinois Extension says to remove dead wood in early spring and cut back to the topmost pair of live buds. Arkansas adds a second step: let the plant make its first flush of blooms, then cut stems back to 3 to 5 feet to stimulate new growth, with more blooms following in a couple of months.

Colorado State gives a caution about how far to go. It defines hard pruning as removing more than a third of the plant’s length, and says that doing so after the first flush removes wood that may not bloom again, while also encouraging new growth that will flower in late summer and autumn. The two sources frame this step differently: Arkansas treats the cut as a way to trigger a second bloom, and Colorado State treats a deep cut as a risk to the wood.

Group 3: cut hard in early spring

Mississippi State says Group 3 blooms on new wood and benefits from hard pruning in early spring. The flowers come on growth the vine makes that season (Kansas State, Arkansas).

New plants and autumn tidying

Illinois Extension says newly planted vines should be pruned to about 12 inches for the first two years, or only the first year for Group 1, and by group after that.

After any repeat bloom in autumn, Colorado State says to tidy up by deadheading but to avoid hard pruning again at this time, or you may diminish next year’s spring show.

Mistakes to avoid

If a vine wilts and its stems die back, that is a different problem. Clemson says to cut off and destroy all the affected parts; see the wilt section of our clematis care guide.