I planted alstroemeria in two separate beds I think in the spring. They have not done much, I believe the first year is always non-productive, and the stems are of the order of 30cm tall. I was expecting them to be ravaged through the winter and then new growth etc. I live in Weymouth and there is a very good chance we will not get a frost this winter. Should I cut the stems down to ground level or leave them? I am concerned that I will not get any flowers on the old growth.