Just one thought on your perennial plantings Jeff, once you bite the bullet and clean out the GB, you may want to plant your perennials in wicking pots set in the media. You can reference JCO's very picturesque thread for a picture of something similar. This way, when you inevitably have to clean out the GB's in the future, you can minimize disturbing the perennials.

I have some smart pots (fabric 5 gal bags) that I plan to set in my hydroton bed in this manner, and I'll post pictures once i have this setup. This may give you a better idea of what I mean.