How to over winter potted gardenia in the Northeast US?
How to Over Winter Gardenia Plant in Northeast
Certified GKH Gardening Expert
Most gardenias cannot survive outside in areas that drop below 15 F in the winter. If you live in an area that gets colder than this in the winter, you will need to bring them in.
If you need to bring them in, dig them up from the ground with the rootball being as wide as the widest part of the canopy (or simply grow them in containers to begin with). I would trim back the plant at this time too, to help it adjust to a smaller root system. Then acclimate it for bringing in the house. This article will help: https://www.gardeningknowhow.com/houseplants/hpgen/using-pesticides-and-other-chemicals-on-your-houseplants.htm