Of the two types of hibiscus, hardy and tropical, only the latter needs winter protection. If you live in a cold-winter area, grow the tropical hibiscus in a pot outdoors. As winter approaches and the temperatures at night drop to 40 degrees Fahrenheit, bring the potted hibiscus indoors for the winter. Even with the best care, the tropical hibiscus may not recover in the spring to bloom as profusely as it once did, but you will be able to keep it alive through the winter. Return the hibiscus to its outdoor location in February or March, when the weather begins to warm.
Cut the hibiscus tree back so that all branches are 4 to 5 inches long. Remove any foliage or other detritus on the soil.
Clean off the outside of the pot with a hose and use a strong stream of water to wash any pests off the plant. Allow the pot and the hibiscus to dry before bringing it indoors.
Place the hibiscus in an indoor area where the temperature remains between 40 and 45 degrees F in full sun.
Spray the plant periodically with water from a plant-misting bottle to provide as much humidity as possible. Alternatively, you can also place the plant on a humidity tray. This is a shallow tray filled with pebbles. Cover the pebbles almost completely with water. Place the potted hibiscus on the dry portion of the pebbles. Do not allow the bottom of the pot to rest in the water.
Stick your finger into the soil every two weeks. When the top 3 inches of soil is dry, give the hibiscus 1/4 to 1/2 cup of water. You want to give it just enough water to remain alive, but not enough to prompt it to produce new growth.