Double bloom hibiscus is part of the tropical hibiscus family. The bloom has five base petals, the same as other single bloom hibiscus plants, but double bloom plants also have multiple petals that develop from the base of the bloom. Tropical hibiscus plants may be grown in the ground in Zones 9 and 10, but the ground around the plants should be kept warm through the cold season. Most growers plant double hibiscus in a container so they can move the plant indoors before the first frost.
Select a container to house your hibiscus plant. A 10- to 14-inch container will work well for your double bloom hibiscus. If you plan to place your hibiscus outdoors, consider a planter with wheels for easy navigation when it's time to move it inside. Hibiscus do not like wet feet, so make sure that the container has good drainage.
Purchase a quality grade of potting soil for your hibiscus plant. They prefer a more acidic soil, so look for potting soils that are designed for tropical plants, such as cactus and palm, at your local garden supply. There is an online retailer specializing in hibiscus potting soil, at hiddenvalleyhibiscus.com, but acidic soils designed for tropical plants that you can find locally will also work well for your hibiscus.
Place 6 to 8 inches of potting soil in the base of the container. Remove the double bloom hibiscus from the grower's pot, and knead the roots at the base to free them. Place the plant inside the container so that the top of the root ball is an inch or so beneath the rim. Fill in around the sides with potting soil.
Add a thin layer of organic mulch around the top of the hibiscus plant to help retain moisture. Water the plant well.
Place the planter in a sunny location that's also protected from wind. Water your hibiscus plant daily if the plant is outside during the summer but less often if the plant is indoors. Just make sure that the plant does not sit in a basin of water.
Bring your potted hibiscus inside before the first frost. Remember to remove any dead material before you bring it inside. It's also a good idea to prune the branches back to within 4 or 5 inches of the main stem before bringing it in. After you prune and while your plant is still outdoors, hose it down thoroughly to remove any bugs and let it dry.