Lilac trunk part rotten

Lee Alexander

Hi, I have an old lilac tree that was in the garden before I moved in (4+ years ago) and over the years it has shot up new shoots. I'm not even sure which is the original tree now. I noticed a large branch of the lilac was hollow and had ivy growing through the middle and was largely of a saw dust consistently in the centre. I concluded that this was dead (dying), so to avoid it affecting the rest of the tree I cut it back to the main trunk from where it protruded from. Anyway, the hollow centre goes in to what I presume is the main trunk, however there is strong growth elsewhere, has lots of other healthy lilac shoots and flowers each year. I've included a couple of pictures (I have given in a good prune after flowering). My question is, do you think my lilac tree has had it or should it be OK.....and what would you do now? 

Blue Onion

Every year you can prune out a third of old branches in a lilac, right down to the ground or base.  Select a few younger branches to grow up.  It's hard to see in the picture, but does your lilac only have a single stem coming from the ground?  Or are the ones to the left a separate section?  Lilacs are tough, once established.  You can cut everything back to the ground and the roots will send up suckers all over the place.  Select the ones to keep as your new bushes, and let those grow to fill the space.  Others can just be chopped off with a spade a bit below ground.  You'll miss a few years of flowers, but the clump will establish quickly.  

This website has good advice along with images to help explain.

https://www.thespruce.com/pruning-lilacs-how-and-when-to-prune-lilacs-1403004

Lee Alexander

Thanks for your reply. Those to the left are separate section and my worry is that the hollow branch will end up compromising the rest of the tree and root systemI suspect only time will tell!