I think there are some specific ones hardy to that zone with lots of mulch and not being too wet as well, but can't say which varieties.

Not sure about the sunset zone 6 but in zone 8b along the states of the Gulf Coast, you can grow numerous Hedychiums. Sometimes called butterfly gingers, their blooms are very fragrant. Hedychium Coronarium is hardy to zone 7. You could also grow Alpinia Zerumbet although this one requires a freeze free winter to bloom in the spring. There are a few other Alpinias that would be hardy as well. There are several Curcumas that would be hardy in zone 7, 8 and 9. Check out Curcuma Elata and Petiolata.

Steve