The time to do that is immediately after it has flowered, assuming it flowers late spring, or just early May if you don't want to wait that long. Angle the cuts on the trunks so allow rain to run off, give a topdressing of nitrogenous fertiliser afterwards, something like Growmore will be fine, and a good water if it needs it.

I think that it has had its day. I would cut the whole shrub down and dig it out and perhaps start again. Ceanothus are not noted for longevity or perhaps try something different.

Well its obviously not that young for a Ceanothus, Jimmy, but I'd give it a chance by cutting right back (both sides) to where new growth is lower down and see what happens.

I think I am with you on this Bamboo I am always willing to give them another chance. But I do appreciate your opinions.

Mine had a similar problem last year and I cut the whole of the dead side off. It is slowly regenerating even though it must be getting on for 20 years old. It looks rather like an overgrown bonsai but its full of flower buds. Worth a try but yours does look as though it might be approaching the end!
Nothing venture nothing win.