Q.Lilac bush
If you cut down a lilac bush will it come back up next summer?
Certified GKH Gardening Expert
If you cut it 6 to 8 inches above the ground, then it will have a better chance, but it should come back up if the shrub was pruned to the ground. Just be aware that it will take about 3 years before it will flower again after such a heavy pruning.
Here is an article that will help: https://www.gardeningknowhow.com/ornamental/shrubs/lilac/pruning-lilac-bushes-when-to-trim-lilac-bushes.htm
Yes, it should do. We cut 2 back a couple of years ago and they still send out new shoots throughout the year. We actually were trying to get rid of them as they are very old and had started to lean very heavily one way to get away from ash trees towering at the side of them. Shame as I did love them. We left the roots in the ground after sawing the tree right down, but they still keep trying to grow. They are quite tough. Careful when you cut it as you could lose the flowers in the spring if you prune it the wrong time.