I've already pruned mine, but in your zone I would suggest waiting a month or so. You wouldn't permanently damage your clematis by pruning them now, but it will encourage new growth and if (when?) you get a killing frost later it will set the plants back. Maybe someone from your zone will come along and give you a better answer.

I'd wait. Even in my very mild climate, I prune my clematis the same time I prune my roses - late February/early March. The only one I'd consider pruning earlier is SAC only because I doubt a nuclear explosion could put that one off :-) And because I like to fertilize at the same time as I prune, that timing in the season makes sense.

SAC???

Gianty,
SAC is a common abbreviation for Sweet Autumn Clematis here :0)

I agree...I am not pruning mine till the same time that Gardengal does...if you don't it will only invigorate your clematis to start growing and with Mother Nature you just never know..boom a late winter freeze or snow storm could come...Jeanne

I lost a SAC several years back after cautiously pruning in April, when I thought it was safe to do so. It was from my g.m.'s garden and I was heartbroken. After that experience, I will always err on the side of caution.

How does one know which Clematis needs pruning and which ones to NOT prune?

Jean

Jean, let's see if I can muddy the waters sufficiently for you :-)

First, pruning is always an option, not a requirement, and any clematis can be pruned - it is just a matter of timing as to when it is most advised to do so. Clematis growers have attempted to simplify the matter by lumping various types of clematis into three pruning groups. I simplify it further into two groups - a "prune annually" group and a "prune when necessary" group :-)

Generally, clematis that bloom before May are included in Group 1 or "no pruning required". This includes a good number of species - C. alpina, macropetala, montana, spooneri, armandii , etc., and any other evergreen forms. These bloom on growth that was produced the previous season. You can prune them of course (anything can be pruned) and especially to control size, as these all tend to be big, vigorous vines but it should be done as soon as possible after flowering to ensure a good bloom the following year.

Group 2 clematis contain most of the large flowered hybrids, also known as the patens group. Pruning of these is again optional as most will produce flowers on shoots generated from the previous season's growth. Usually the recommendation is light pruning early season to remove the worst of the tangled vines and a second light pruning after the first flush of flowers to encourage rebloom. In warmer zones with long growing seasons, these types of vines can be hard pruned if desired and they will still flower well, just a bit later than those left unpruned or pruned very lightly.

The last group contains a wide assortment but can be characterized by vines that bloom on new growth and tend flower in midsummer or later - all the viticellas and their hybrids, all the herbaceous forms (C. recta, integrifolia, heracleifolia, etc.) and all the late blooming species: SAC, tangutica, orientalis, etc. These can be hard pruned annually.

To complicate the issue, there is yet another group that is hard to classify and is commonly listed as Group 2B or sometimes 2/3. These are the languinosa group which bloom freely on both old and new growth. Pruning techniques on these vary with the grower, but they can be hard pruned, partially pruned or left unpruned.

Simple, huh?? :-) Actually, most of us tend to overcomplicate the issue. It will not hurt your vines to leave them unpruned or hardprune them all each season, but as with pruning flowering shrubs, the specific timing will determine subsequent flowering. There are countless sources that will tell you what pruning group your specific vine belongs to (COTW is an excellent source) but you need to know what vine you have. If you don't know, watch the flowering time of your vine and prune accordingly or post pics here for help with ID.

And finally, it is often recommended to hard prune newly planted clematis their first spring after planting regardless of type. This encourages strong root development as well as the generation of additional stems from the root crown leading to a more vigorous and wilt resistant vine.