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.?