Something's going on with my barberry bushes!!!!

[bergie42]

My barberry bushes aren't blooming on top at all, but there are leaves, and even the little blooms down on the bottom.

I am trimming them down a bit, and each cut I take shows that the branch is still alive and green.

Should I cut them all the way down to where the leaves are, or just trim them down a bit? This is the first time this has ever happened. Thanks.