Hi Jacquie.
Do you happen to remember if your gardenia was marked hardy for zone 7? Also, do you remember how large it is supposed to be at maturity?
It will make it much easier to ID if you do. The link below lists some of the zone 7 cold hardy gardenias available. Perhaps they may ring a bell with you. If not, then I would suggest clipping a stem with a bloom and a couple leaves and comparing them with the gardenias at the store you got this one from.
http://allthedirtongardening.b...
