Be careful when you trim.
The dormant flower buds for next year are just below the blooms for this year.
Trim those off and you have cut of a bloom for next year.
My brother once trimmed our old lilac the way you trim a hedge and it was years before flowers were more than few and far between.
I used to trim my lilacs so they were clear approx. five feet above the ground, looking more like clumps of small trees but over the years I think that did more harm than good as I have not had steady good blooms for awhile now, so now I let them get more dirty with new growth.
Trimming old blooms though does improve the bloom for the next year.
ON occasions when I have a burst of energy I get out the step-ladder and get as many as I can.
Weather snaps are very hard on lilacs and a drop into the twenties, as it did up here this year cut way back on the number of blooms.
