Yes, I read your lilac pruning advice before I posted. (BTW, props to you and Sally Spillane’s show, where I discovered this site.) I pruned a healthy, yet seemingly old big root branch in October 2006. The lilac was in full, resplendent bloom in May 2007, when the cat died. The burial hole was about a foot from the base, and about 3 ft. deep. The lilac was not at all uprooted. Nothing has changed in terms of soil or light; it gets over 8 hours a day of sun. I do not recall any pruning since Oct 06, though my memory might be faulty. Could the lack of bloom this season possibly be the result of the pruning that took place over 18 months ago?