Can I divide a lilac bush that has turned into a tree?

[H.C. Heartland]

In the corner of my mothers fenced in English garden, she has a beautiful lilac 'bush' that looks more like a tree. At the root system, it seems to have grown in two clusters which makes me think we might be able to divide it even though I know you would normally dig it up. She says the blooms are less and less this year and now it is covering the window. But I love the scent of lilac and would like to know if I can divide it and possibly save half of it. Does anyone know if this is possible? If so, what would you advise?

 

[firelily99]

I have tried to find a definitive answer on this but haven't seen anything. If you do have two distinct clusters then you can probably divide it but I would see what kind of a root system you have. If it is blooming less then it might need to be fertilized and/or pruned back to encourage new growth.