There's a number of ways this can be approached and always with the acknowledgment that pruning recommendations are guidelines only. Once established, clematis do not require pruning but it is often done to maintain the vine's appearance and promote flowering at a height where the flowers can be properly enjoyed.

Nelly is a group 2 clematis and the favored practice for this type is to prune lightly in late winter/early spring to around 4-5 feet. Another very light pruning (perhaps removing only 18" or so, essentially those portions of the vines carrying the spent flowerheads) directly after the spring bloom will encourage a late summer into early autumn rebloom. In those areas of the country with a long growing season - your zone 8 - a heavier pruning in late winter/early spring will result in a later but heavier and longer lasting bloom period on a more compact vine.

If the vine is not yet well-established - going into its first full growing season or even the second - a hard prune back to the third set of buds is recommended. This encourages more stemming from the base and dense branching, allowing the roots greater ability to catch up with the top growth and reduce the chance of wilt. This practice is recommended for any type of clematis regardless of pruning group.

A good many popular clematis are hybrids, so growing them from seed will not guarantee a vine that is true to name, although you may get great seedlings. If you want a named cultivar, it is best to purchase one or to start one from cuttings (difficult) or by layering (relatively easy).

Xtal. welcome to the wonderful world of clematis obsession. Just a word of caution about clematis in your zone. You would be much better off growing type III clematis than the large flowering hybrid type IIs that Nelly Moser falls into. The type IIIs are much less likely to succumb to clematis wilt and are less likely to brown out in the middle of the summer than the type IIs. In my zone 7a garden in the middle of NC, all of my type II clematis turn disgustingly brown in the middle of the summer. This however doesn't mean that they are dead, but that the leaves desicate in the hot summer sun.

My treatment of type II clematis as a result is that they are treated as type IIIs and cut back severely in the winter or early spring to within 6 inches of the ground. They will flower later in the year and then by midsummer turn brown and ugly. At that point, they are cut back once again like in the winter, kept well watered, and given some fertilizer and they bloom again once it cools down in the fall.

Another option is to do as gardengal suggests--only trim them back to remove deadwood in the early spring, they will flower sooner than if cut back as severely as I suggested, and then cut them back severely in midsummer after they brown out to get another round of blooms in the fall.

Although the type II large flowering hybrids are the ones mostly likely in bloom and present in the garden centers in the spring, think outside the box and try the many different clematis that bloom later in the season and that fall into the pruning III class. I think you will have a much better first experience with clematis!

Good luck!!

I have a lot of type II's and type III's and I treat them as Miguel does. They do very well with this type of pruning in areas with a long growing season. For some reason, I haven't had much problem with wilt on my type II's. I have no idea why.

Carol