Hibiscus shrubs and trees are a tropical and sub-tropical species that are not frost hardy and are sensitive to temperature fluctuations. They can be overwintered outdoors in climates where frost does not commonly occur and overwintered indoors where frosts are common or sporadic. The ideal ambient temperature range for hibiscus is between 55 and 75 degrees Fahrenheit.
Move your hibiscus to a sunny location indoors before the first frost occurs in the fall. Choose a location to ensure that the plant will receive a bare minimum of five hours of bright direct sunlight daily with more like seven or eight hours being optimal.
Keep the soil lightly moist at all times during the winter when feeling one inch down into the soil. Refrain from siting the plant near heat and air conditioning vents or anywhere it will be subject to drafts of air such as doors and windows.
Return the hibiscus to its outdoor growing location in the spring after the last frost is well passed. Make the transition slowly placing the plant outdoors in a protected and slightly shady location, then in filtered sunlight and then into full sun over a period of a few weeks until it is living in full sun over the summer and early fall.
Mulch around the base of outdoor grown hibiscus in the late fall with two to three inches of organic mulch to hold moisture in the soil and protect the roots from temperature fluctuations.