Looks a lot like jackmanii, which, while it can be a bit variable, tends to have 4 sepaled, 5-7" blooms of a deep purple color. Clematis jackmanii is a very robust and heavily flowering vine and is very widely grown and sold. It is one of the earliest developed of the large flowered hybrids and is considered a parent of many modern day hybrids.

It is rather easy to determine what pruning group a particular clematis belongs to according to the time it blooms - Type I clematis bloom very early, usually before May and bloom on old growth. Pruning is usually limited to immediately after blooming only to control size.

Type II clematis bloom anywhere between May and July and frequently with a late summer/early autumn rebloom. Most Type II's bloom on a mix of both old and new growth, so pruning established vines is done lightly in late winter and again lightly after the initial bloom flush. Virtually all Type II clematis are the large flowered hybrids.

Type III clematis are later flowering and bloom from mid to late summer (July) often well into fall. Jackmanii falls into this category. These bloom on new growth produced the current season and established vines are hard pruned each winter. Most of the vines included in this group are species clematis or viticella hybrids with a few large flowered hybrids thrown in the mix to confuse you :-)

It is helpful to remember that pruning "rules" are only pruning guidelines - you can choose to follow them or not. Generally not following the 'rules' will only lead to a missing or sparse bloom or a tangled vine, not death! Really, the only pruning practice I would encourage you to follow without deviation is to hard prune any type clematis the first couple of seasons in the ground. This just makes for a more well-developed root system and mutilple vining stems, among other features.

Thank you so much! Now I can look it up. Thanks also for the explanation of the different types - now it make much more sense.

Jackie