What type of clematis is it and how have you been pruning it? Any clematis will eventually develop brown woody stems if not pruned.

The clematis was here when we moved in, so I have no idea what type of clematis it is. Here are some pictures of it:

http://www.imagestation.com/6193170/3906015395
http://www.imagestation.com/6193170/3906015957
http://www.imagestation.com/6193170/3906015960

Can you id it for me? Is there anything I can do to the woody stem?

It looks like C. viticella 'Venosa Violacea'. This can be cut back quite hard in late winter, but my experience with most viticellas is that they will grow vigorously regardless of the amount of pruning and still produce more foliage and flowers concentrated at the top of the vine. The bare "legs" are pretty much a fact of life :-) Others may have a different take on this.

For this reason, I prefer to allow my viticellas to scramble through shrubs or small trees rather than train on a trellis or arbor. This way, the bare portion of the bottom of the vine is much less noticeable.

You have clematis "Venosa Violacea"..the reason you are seeing so much "woody" stems at the bottom and flowers at top is that it's a pruning group 3 and blooms on the new vines produced during the growing season..hard prune it in late winter/early Spring..I don't see your zone listed...In my zone 8B of Texas I hard prune after the bloom period is over and get a 2nd and sometimes 3rd bloom period....Jeanne

Cut it down to a foot tall and it will sprout out more vines and bloom lower. Pinch back the new growth too. Whether you can do this now and again next spring depends on your climate.

If you are really cold you probably should wait and do it in the early spring. You don't want all the new growth to be frost damaged or the plant still actively growing during frost.

(This growth pattern is normal for all unpruned Clematis)

I live in southern ontario and I think I'm in Zone 5. Thanks for all your help. I'll cut it down to a foot tall in the early spring. Is there any rules I should follow when pruning it?

I would prune right above the 3rd leaf axil and fertilize with some rose or tomato fertilizer next year...do it about the same time your Forsythias are in bloom or you do the first pruning of your roses...that's all!..Jeanne

Ditto to what everyone has said who said to prune it down to a foot or so. My oldest clematis are type III viticellas--Julia Correvon and Purpurea Plena Elegans. I prune them hard down to 3 or 4 inches each year. I have no bare legs on them and they retain their leaves down low. The only reason a type III viticella will develop bare woody legs down low is if it not pruned down low each spring (John Howells in his book on viticellas recommends cutting them to ground level!) or if you are somehow shading out the lower leaves and they fall off as a result. Remember, the purpose of leaves is for photosynthesis. If they are not provided enough light due to shading by other plant growth or some other type of structure, they will not be able to photosynthesize and therefore the plant will allow them to die off and fall off.