I have a 30-year old lilac tree that has gotten far too big in the mantle (15/20 ft across) with a height of 20 ft (approx). I want to reduce its size both in height and mantle. How severely can I cut this tree back, and when can I do it? Many thanks.
Resizing Old Lilac Tree
Certified GKH Gardening Expert
I would not prune it back by more than 1/3 in any one year. Cutting it back further than that could harm the plant. This article should help with pruning: https://www.gardeningknowhow.com/ornamental/shrubs/lilac/pruning-lilac-bushes-when-to-trim-lilac-bushes.htm