All is not lost! This is a wonderful clematis of pearly white that captures the light and almost glows. Prune the various vines back now to the first branching that is showing two growing buds, generaly found within the first 12 inches. Consider if the plant has received adequate moisture this winter and if not water. Here on the front range of Colorado I will give a first feeding in late March or early April, something with 3-12-12 proportions. If it is getting adequate sunlight on the vines with the roots mulched and kept cool, your clematis should respond with vigorous growth and many blooms for your enjoyment. Happy gardening!