Lilac shoots all over the place...

Hello,

I have recently moved house and subsequently taken over a new garden.  I want to get my head around the planning of the garden jobs for the year.  I have 3 lilac trees in the garden all seem quite old and with lots of new root shoots all over the place.  My solution would be to dig each up in turn, remove as much of the roots as possible and replant in a large plastic container in the ground to prevent this happening again.  However they are all just coming into flower, should I wait until they end flowering, then complete the work just before they go into their major growth time for the year.?

What you're suggesting isn't practical - digging up an old tree risks killing it from root damage, and cutting off most of its roots is likely to finish it off. Further, trees respond to root damage by suckering, so wherever you damage the roots, you will get more suckers (if the tree survives).

The way to treat suckers is to brush back the soil to expose the sucker, then either cut it very close to the root or tear it off. It is a perennial problem with lilac, but controllable if you keep on top of it.

Yup, I agree. Lilacs are notorious for suckering and tearing them off from the tree's roots is the accepted way. Or if like me and a touch lazy, trimming them down to the ground with secateurs, but that way they WILL return.