Hand fork around the root area and add some multi-purpose plant feed and gently fork this into the same root area soil.
make sure it is watered well in the hot dry season, I take this plant is in the garden soil and NOT in pot's, you soil in Florida can be exceptionally free draining so this winter I would add a thick layer of humus rich mulch around the roots so next spring / summer the soil has a little extra help with regards holding onto water as you use the hose or watering can.
These plants can eventually form a huge fat clump and spread way beyond expectations so make sure there is plenty room around the roots area so the plant can expand.
I dont think you should expect a vast improvement on the size for maybe the first 4-5 years then it should just move out and up.
Hope this helps you out a bit.
Best of luck. WeeNel.