I live contained by TN and want to know if gardenias do powerfully within thein the winterswers from millions of concrete ethnic group.?
Answers: Almost. grow them in pots and bring them indoors, garage, greenhouse etc, when freezing temps are expected.
I muse what you are asking is if gardenias are winter hardy in your nouns.
Tennessee is Zone 6, which means your avg. minimum temp is -10 up to 0 degree f. Gardenias will not tolerate that cold of temperature.
They are typically Zone 8-10 near a couple of claims of being cold hardy to zone 7. which is 0 to 10 degree.
What you can do is bring them indoors overwinter.