I have a Sweet Autumn clematis, that I planted earlier this spring. It is growing fine, but have noticed some of the ends are wilting. Is this because it is new, and the roots have not caught up to the vine growth? Should I pinch the ends? I planted it in a part sun location, at the base of a small elm tree, about 1' from the base, I dug a large hole, and I added a lot of good compost to the soil when I planted.