Not sure About Hawaii, here we dig them before the frost and store away till spring. I would think you could divide the clump, fertilize, and re-plant when the blooming season is over.
I don't live in a no-snow area but I would think you need to create winter for bulbs. I know I've read something about needing to put bulbs in the refrigerator for a certain amount of time to stimulate hybernation.
I had asked my dad since he had many gladdiolas plants and for him-he just digged out the bulb after it flowered, dried it, seperated it, and then planted it again and it worked. So, I am going to try his technique out and hope that it works.