In the March 13th Sun.Trib., the garden section highlighted growing clematis. I have a pretty one in my backyard, about 4yrs.old, and have never pruned it back. What would be your suggestions on where to start?

Clematis are typically placed into 3 categories for pruning purposes. The first group are the very early bloomers. They produce flowers on last season's vines. These should be pruned right after flowering but only if there are constraints on plant size. Group 1 includes C. alpina, C. macropetala and C. montana. Group 2 produce flowers before mid June. They bloom on vines produced on last season vines. they may also bloom again in late summer or fall. They can be pruned in late winter or early spring as buds swell. Cut back to strong healthy buds depending on eventual size goal. Group 2 incldue the large flowered types ie Nelly Moser. Group 3 are late flowering. Prune these down to strong healthy buds near the base to encourage new shoots from crown. Now you just need to figure out which one you have.