Clematis Pruning

The 3 types of clematis
There are different types of clematis with different pruning requirements, this may simplify things by using these three main clematis categories.

Early Bloomers
These flower on old wood from the previous seasons growth and thus should not be pruned. These bloom in the spring. If you would like to prune it to shape, do it after it blooms. Pruning later than June or very severe pruning will result in fewer blooms the following spring.

Mid-season bloomers
Bloom on wood from previous season as well as from the current seasons growth. Pruning on these varieties is optional. However, if they are frozen back to the ground, they will bloom later in the season than they would have, had they not been pruned. They will still perform very well. This is true for all clematis in this section with the exception of double flowering varieties (those with an indefinite number of petals that give it an unusually full look). These will only have double flowers on the previous seasons growth, and thus will not perform well if pruned hard. It should also be noted that the doubles in general are not as vigorous or as free-flowering as the singles.

Late-season bloomers
These bloom on wood grown during the current season. They should be pruned hard during dormancy (leave 3 pairs of leaves on pruned, it will still bloom. An option here is to prune half the plant back. This will give you a taller plant with blooms lower down.