Sure you can trim clematis back when transplanting to make the transplanting easier. I would leave 3 to 5 sets of leaves on the plants when I cut them back.

Forget the idea that clematis need cool soil to prosper. They need moisture that co-exists in cool soil so keep them well mulched and watered once planted. Type IIs tend to burn out more in the extreme sun so if you have any of them you may want to plant them where they can get some shade in the hotter parts of the day. Type IIIs in my experience tend to handle extreme heat better than the type IIs, but even they can look ratter during hot dry summers. The best thing about growing them in Texas is that your clematis will bloom sooner than in cooler parts of the US and if they do get ratty looking after their first bloom flush, you can always cut them back severely, keep them watered and fertilized with a low nitrogen fertilizer, and you may get two or three flushes of blooms on them over one growing season. Jeanne who frequents this forum lives in Texas and she gets 3 bloom flushes on some of her clematis. Perhaps she will chime in here also.

nckvilledudes, thanks for the information, now to show my real ignorance regarding Celmatis, what are Type IIs and Type IIIs? Can you point me in the right direction for a good knowledgeable source to educate me? Besides yourself and other GardenWeb folks? A really good illustrated book perhaps?

Thanks

No book has all Clematis listed, there are just too many.

There are several groups or types in Clematis and how they are pruned depends on what group they belong in. All should be pruned hard the first couple of years though.

Clematis on the Web's site is most comprehensive.

Here is a link that might be useful: Clematis on the web

BorS has pointed you in the general direction of a good resource on clematis and on how to prune all classes of clematis the first year at minimum.

Generally speaking, type two clematis flower earlier in the season since they bloom on older wood produced the previous year. They are rarely pruned back except to remove dead wood or contain their overall size. Notice I said generally speaking because in my zone, I can prune my type IIs back after the first flush of blooms and get more flowers later in the season on wood produced after they are cut back.

Type three clematis are those that bloom on old wood later in the season than the type twos and are generally pruned back to within a couple of inches of the ground in winter or early spring. If you don't prune them back, the stems get older and woodier and the flower production may be limited and will exist only on the newer wood above the older wood.

I think one of the most indispensable books on clematis is An Illustrated Encyclopedia of Clematis by Mary Toomey and Everett Leads. You can often find discounted used versions on Half.com or Amazon.com. Just be careful though because once you get the book, your list of wanted clematis will grow to unimaginable lengths.