This bush was potted in a 5 gallon bucket for 2-3 years, as we were in transition. It has since been planted for at least 2 years, but has never bloomed. We have never pruned it, yet it is only about 3 feet tall. It gets more than 6 hours of sun a day. I have other lilac bushes, but this came from my husband's mother, who has since passed away. What can we do to make our poor little lilac bush bloom? Any help would be greatly appreciated!! Thanks and Blessings!