I have an ivy topiary ring that I started several years ago.

It looks great and I have root pruned it twice. The diameter of the ring is starting to get a bit thick but I can't really trim it anymore because of the woody vines underneath.

I was wondering if at some point I need to start over with fresh new vines because this ring will just get too woody?

Can ivy indefinitly produce new green shoots on the same old wood?

I keep it healthy with yearly root pruning and fresh soil, regular water, a systemic...I'm not having a problem with it thriving. I trim it about every two weeks or so but as it's in a bay window area we sit in all the time, I'm always examining it.

I hope all this makes sense!