I pruned one of our Lilac bushes this after noon following my round of golf. It is a shrub that dates back to the farm where Elaine grew up. When her folks moved to town back in the mid-fifties, they brought a part of the plant to their house on Locust street here in Seward. When we bought this place in the early 80's we brought a start down here. It has done well over the years. I have done some pruning nearly every year but today I really worked it over. This is the ideal time to prune, right after they have bloomed. I cut out all the old wood and trimmed the tops of even some of the smaller stems. The "book" says you shouldn't take more than 1/3 of the growth while removing any stems approaching 2" in diameter. In extreme cases, it says you can cut the whole bush down to about 10 inches high. It will take about 3 years for it to bloom after that kind of drastic "butchering". We had a Lilac bush out at the farm where I grew up too. It was in the front yard near the well. Dad trimmed it one time by leaving 3-4 big stems and cutting away everything else. It looked like a small, multi-trunked tree with no foliage below about 6'. Mother wasn't pleased but it came back to be a nice bush after 3-4 years.