I'd get it going with a few deep, deep soakings so you get some new growth sprouting at the very base, then cut off all the old stuff right down to the base of the plant, and do what is needed to get that new growth really going strong. But you might want to wait until mid September, when nights start cooling off.

Longer term, I think it's in Pat Welsh, Robert Smaus, or one of the SWG's entries on Echium that you remove the stems that have bloomed after they've finished blooming. The stems only bloom once, so you need to encourage new stems every year.