BTW, JuliaJayne, I didn't mean to ignore your original question. Being in the South, I haven't had much experience with harsh winters... until this one. I actually have quite a few clematis of my own that didn't make it into the garden before the hard freezes hit us, so you and I are in this experiment together, to so to speak! Mine greened up during the interluding warm weather and one even set buds. Tough little guys, these clematis. I think you are on the right track... providing just enough moisture to keep them viable without rotting the roots.
Perhaps Louise (Venu209) or Arlene (Pirl) can offer better feedback on this topic. They both garden in cold winter environments.
