Cover it with a hard plastic/wood container with a blanket on top, hope that doesn't blow away in the wicked wind with this front and keep your fingers crossed. I have seen the rare gardenia resprout from the crown after getting frozen to the ground in my zone 6.

If you have any leaves in your compost heap that haven't composted yet, I'd pile them up on the gardenia and then cover with row cover (ie gardening cloth that allows the plant to breathe). You can do this each fall. Covering that with the bucket, as @Christopher CNC recommends when it's going to be cold is a good idea, but you might not want that on your plant all winter.

at these temp extremes.. which roughly translates into EXTREME ZONE PUSHING ... prayer is the usual suggestion ...

and it rarely works ...

it probably down to whether the ground freezes.. or gets cold enough to kill the roots ... many things can recover.. if it only dies back to the ground... but nothing survives if the roots die..

ergo.. mulch them up to keep the soil warmer than without the mulch ...

ken

ps: i thought i could beat ma nature.. and lost a lot of money on that pipe dream.. SHE ALWAYS WINS .... period ,.. its usually called a 10 year storm ... floods.. freezes .. tornado.. hurricanes.. etc.. MA NATURE ALWAYS WINS ...

I found a little desktop heater on GoNC for $4! So I took some chicken wire, wrapped it in black plastic, and placed it over the gardenia, then stuck the heater in there (with the plug raised up on a stake so it won't get wet).

It's obviously not a long term solution, but hopefully it'll work for the next 3 days!!

I'm pretty lucky that I bought a large greenhouse earlier this year. I wired in a 30,000 BTU heater, and it's staying a toasty 74 :-) Most of my other plants are safe in there, but God only knows what my electric bill will be for this month!