Hibiscus are good performers, both in the garden and in bright areas inside the house. If they receive just a small amount of care they reward us with many magical blooms throughout the year. Here, in short, is what they need:
Most important, a WARM place where their tropical origins are respected. It is often said that hibiscus like much the same conditions as people and with temperature, that is pretty much true. For best results and lots of blooms, hibiscus should be located where the temperature remains between 60 and 90 degrees most of the time. Short periods of either hot or cold will not injure them though they may show their displeasure by shedding a few leaves or dropping some developing flower buds. If temperatures routinely drop below 50 degrees, particularly at night, most growth and blooming will stop until it warms up again. Flower size will become much smaller and the occasional blooms may also be misshapen. For more information on cool weather growing: "Hibiscus Care ~ Wintering Tropical Hibiscus".
Temperatures below freezing will injure hibiscus. Factors such as how cold and for how long, the age of the plant, and whether it is dehydrated determine how extensive the damage. Under 30 degrees for many hours will most likely kill the plant entirely. Such temperatures should be avoided.

Temperatures over 95 degrees will often cause most flower buds to drop off. Hibiscus can survive temperatures even as high as 115 degrees, provided they have adequate water. When the weather is hot, it is best to maintain a steady supply of water to the plant, rather than have it go through wet/dry cycles. For more information: