It can take several years for a clematis vine to mature and start flowering. I think that soon your patience will pay off. Just remember the bottom part of the vine likes shade and the rest of it loves the sun. Go to my most recent blog (Need A Rainmaker) and you will see that I used a statue to provide shade to the lower part of the vine which is four years old and is just now coming into its prime.

Loosestrife2 is right. The roots need shelter. I either plant in front of it something like, eg Bergenia, lavender, or use a large rock to protect the base. An ornament looks prettier than a rock though!

I don't agree -most hybrid Clematis usually flower in their first year, even if its only one flower, the species may take a year or two. Even when bought as very small plants, they've often got flower buds present.

Which variety of Clematis is it? Is it in the ground or in a pot, in sun or shade, and have you ever pruned it?

Bamboo is right, it should have flowered by now. I would guess it's getting cut back at the wrong time, either by humans or snails/rabbits etc.