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 !