The genus Clematis is usually split into three groups, based on the time of year that flowering takes place as a result this web site has a separate entry for pruning each group.
The pruning of the particular species is dependent on which group they're in. The different groupings and species require pruning in particular ways, so there is a note of caution: if you're not certain what kind of clematis you have then we won't prune! We'll wait until they've flowered! There are so many different varieties that's it's best left until flowering, rather than guessing, even when that guessing is based on pretty good knowledge!
Group three Clematis
This group of clematis are those that flower after early summer on the current year's growth.
We'll prune these in late winter to early spring by cutting the top growth again down to a healthy pair of buds which are above the base of the stem from the previous season.
including the many varieties of C. viticella, C.orientalis, C.texensis and lots of large flowered varieties, such as C.'Gipsy Queen' and C.'Hagley Hybrid'. These respond well to hard pruning.
This is most often evidenced by the growing tips turning black and the plant basically collapsing. We obviously try to ensure that this doesn’t happen. Unfortunately the cure is farily drastic: we’ll cut the flower back to ground level and wait for new shoots to appear.
The aftercare of Clematis
During our on-going pruning of clematis we’ll ensure that any new growth is supported either by whatever is to hand (tree, downspout, trellis etc) or by a stake. We’ll also give the plant a good feed with fertiliser after pruning and ensure that there’s a good mulch spread around the base of the plant.