I have a number of what I would call "common lilacs," in while, dark purple, and, uh... well,'lilac.' Then I have another bush, a little less vigorous, about 8', smaller flowers, smaller leaves, does NOT sucker. I always thought the smaller bush was a "French Lilac," but now I understand that "French" = "Common." So, what's the little lilac?
Certified GKH Gardening Expert
There are many types of Lilacs, including Dwarf varieties.
These links will help you.