Frost Proof Gardenia are prized for the strong sweet scent of their flowers, which grow be very large. Frost Proof Gardenia were first cultivated as a house plant. Gardenias usually demand high humidity to thrive, and bright (not direct) light. They flourish in acidic soils with good drainage and thrive on 68-74 F temperatures during the day and 60 F in the evening. The benefit of a frost proof gardenia is in its name – they have been breed to adapt well to cooler climates.