Hi Angie-welcome to California !
You shouldn't have to do anything special to your potted
plants for winter here.
Just food, water and sunshine. No more care than any container
plant really. The gardenia would appreciate misting and as much humidity as you can give it.
I lightly feed all of my container garden year round.
Of course, if you get a frost, you can move the pots to a roofed area or cover them with a sheet.
I wasn't quite sure what you mean, but there's no special thing to do to the
plants.
I wish you every happiness in your new home !