How do I prune mature lilac bushes and get new shoots to grow?

Question

I have two lilacbushes that are probably forty years old and twenty feet high. I cut off some of the old stems near the base last year understanding that new shoots would come up. They didn't. My understanding was that the new shoots would produce flowers in two years. Any suggestions as to what went wrong?

Answer 1

Maybe the new shoots didn't come up because they were pruned at the wrong time. Usually, pruning should be done immediately after the flowers have died off.

Hard pruning is done in late winter ...March or early April... to induce shoots to develop during the growing season.
"cut back the overgrown shrubs over a three-year period. Begin the procedure by removing one-third of the large, old stems at ground level in late winter. The following year (again in late winter), prune out one-half of the remaining old stems. Also, thin out some of the new growth. Retain several well-spaced, vigorous stems and remove all the others. Finally, remove all of the remaining old wood in late winter of the third year. Additional thinning of the new shoots should also be done. Since lilac wood needs to be 3 or more years of age before it blooms, this pruning method should allow you to enjoy flowers every spring. This is my usual mode of rejuvenation pruning lilacs."
http://www.helpfulgardener.com/lilacs/03/pruning.html

Answer 2

prune after it blooms so you can enjoy the blooms. Cut back inside if you can to open up to give it an airy feel inside. Cut out the maple shoots that you see - they are really weeds to you in this location. When you prune it prune it back as far as you feel you need. Bear in mind there is a chance that you are sacrificing next years bloooms. This is going to be a small price to pay to ensure that you will have a healthy bush for further years. The general rule when pruning is to prune back for shape and form and then after that prune hard by cutting away about 1/3 of the branches to air out and refresh to tree/bush. Any branches that seem to be rubbing against wach other need to be removed. Also branches going straight up should be pruned off as they are anyway unlikely to produce blooms and just prevent airflow within the bush. Welcome to your new pkace. Enjoy the home and the garden Oh yeah, the reason sometimes for the late winter idea is you cna prune away anything that has died.