Honored as Hawaii's state flower, the hibiscus is a widely known and much loved flowering plant that naturally thrives in tropical and sub-tropical climates. Hibiscus are naturally hardy outdoor plants in warm-weather areas such as south Florida, Hawaii, southern California and other locales where temperatures constantly remain above 50 degrees Fahrenheit. In other locations, hibiscus can be grown outdoors during the summer months with proper care.
Start your hibiscus in a container or in the ground in a partly shaded area to gradually expose it to the sun without too much strain. As it grows accustomed to direct sunlight, gradually move it to a mostly sunny location. Easing your new hibiscus into its sunny location provides the best care for the plant, especially for its glossy leaves which can become dry or burnt if exposed to full sun immediately. Experts note that the ideal sun conditions for hibiscus growth and flowering include two to four hours of direct sunlight with the rest of the time in partial shade.
Select containers that are at least as wide as they are deep, because the plant's fine feeder roots grow and spread out horizontally from the plant. Hibiscus need good drainage, so buy a container or planter with either bottom or side drainage holes.
Use light soil. A combination of 80 percent potting mix and 20 percent sand is commonly used for potted hibiscus. A thin layer of mulch can also be added to the top of the soil mixture to hold in moisture, especially during the hottest days of summer.
Water hibiscus regularly, especially during hot weather, but avoid providing too much water as the roots of the plant should not sit in water or extremely wet soil. Hibiscus leaves will droop when the plant is not getting enough water. A good rule of thumb when deciding on whether your hibiscus needs water is to stick your finger down into the soil around the plant to about a depth of one half an inch. If the soil is dry, the hibiscus should be given water.
To produce big, beautiful flowers, hibiscus require regular fertilizing. A fertilizer high in potassium is best, and garden centers offer fertilizers specially made for hibiscus. Fertilize according to directions. Do not over fertilize, and always water your hibiscus after fertilizing so as not to burn the plant or its leaves.
Bring outdoor hibiscus indoors during the cooler seasons to survive. Hibiscus planted directly in the ground can be potted and brought in. As air temperatures begin to drop below 40 to 50 degrees F, it is best to move your hibiscus in to avoid stressing the plant. Indoors, the hibiscus should be kept in a warm, sunlit location until sustained warm weather permits it being moved back outdoors.