I need to stain my wood fence and have lilacs that are growing along the way. They are at least 30 yrs. old and haven't been pruned, ever. If I prune them now (I live in Zone 5), will they survive? I'm afraid to cut them down to the level we need to work on our fence. Please advise.
Pruning Lilacs in the Fall
Certified GKH Gardening Expert
You can prune them now, but they would most likely not bloom next year if you do. They would recover for the year after that though.
If you decide to prune them now, we would recommend you do so before the end of September, as if you prune them after that you are risking them putting out new growth that will not be sturdy enough to withstand the winter.