|I planted three hydrangeas four years ago. They get full sun and come back every year, however they have yet to flower. I must confess, the first two years I did not realize they flower on old wood and I cut them back. Year three we had a late frost, and I neglected to cover them, so once again, no flowers. This year, again a late frost, but I covered them and new growth is coming in fast, but nothing seems to be appearing on the old wood. I also gave them garden sulfur so the flowers are blue. What am I doing wrong?