Q.saving an old Lilac while building next to it
We have an old lilac tree whose base has split into about 6 trunks. We have cut back 2 of these at the end of May as they were at 45 degree angle to the rest of the trunks and at immediate danger of falling and splitting the base. We want to build a concrete base for a shed and need to build where these two remnants of trunks are. They are already sprouting. Should we cut them right back to the base at possible risk of damaging it, or is there another way to deal with them to keep the main trunks, and the tree, safe?
I would certainly consider removing this Lilac and it's roots before pouring the concrete. From experience, concrete is expensive, a new Lilac tree is quite inexpensive at the garden center!
Here is an article with more information.
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/damage-from-lilac-roots.htm
