HIBISCUS: (A collection of advice from the internet - some references are to potted plants)

WATER: Hibiscus like water but don't over water. The soil needs to dry up between applications to protect from root rot. It's important to refrain from watering with cold water in winter.  A properly watered and fertilized plant is better able to resist problems.

HOW MUCH SUN: They do like a lot of direct light, but under a blazing sun from dawn 'til dusk with temperatures in the 90s, many of these hybrids will reduce their blooming. A little shade during the heat of the day and they will reward you with more and larger blooms

FERTILIZING: For prolific flowering, hibiscus must have regular feedings every week during the growth period, March-October. Water soluble formulas can be used with every watering. I usually water 9 times with fertilizer and then flush with clean water the tenth time. This will prevent salt buildup in the pot. Never fertilize dried out plants -you may damage the roots. First re-hydrate the soil by putting the pot in a bucket with about 2" (5 cm) of water. Add a dash of regular dish detergent to break water tension, this will allow the water to better penetrate the dried out soil. Leave pot for 30 minutes in bucket then return to planter. When the soil is once again moist through you may fertilize.

Choose a fertilizer with a low phosphorous value: N (Nitrogen) 20 P (Phosphorous) 5 K (Kalium) 20 is close to ideal. Too much phosphorous makes for many fine leaves but few flowers. Hibiscus also need TRACE elements, especially iron and magnesium (Epsom salts).

REPLANTING: Hibiscus have good root systems. Healthy roots are white to tan in color, crisp and plump. Replanting is usually carried out in spring, February-March. Often you can at that time observe roots poking out of the bottom of the pot through the drainage holes. When the root ball has been carefully loosened and lifted out of the pot, it can at times be seen that the roots are wrapt around the inside of the pot. These roots must be loosened up properly and perhaps shortened. Completely cut away any dark brown and soft roots. I doesn't matter if some of the roots break off. A root pruning might have to be carried out if there is too much roots. Replant in a one size larger pot than before.

PESTS: The most common pest on hibiscus to benefit from a dry indoor environment is Spider Mites. The most effective way to get rid of them is showering the plant with lukewarm water, strong blast, at least once a week. Make sure to clean the underside of the leaves. Daily water spraying may also be useful. Aphids can be treated in a similar way. If you suffer a severe pest infestation use soap water or commercial insecticides. Please note that insecticides containing the active ingredient Imidacloprid will encourage spider mite infestations; they thrive on it!

YELLOW LEAVES: All hibiscus have yellow leaves now and then. A few yellow leaves usually only mean that those leaves are getting old and need replacing. If your plant has many yellow leaves it is stressed. The most common causes of plant stress are under-watering, drastic environmental changes or pest invasions, especially spider mites.

BUD DROP: Bud drop is often the result of drought or severe pest attacks. Some double flowering varieties are more prone to bud drop than other hybrids, why is unclear. Attention! Hibiscus in bud should not be turned because then the buds almost invariably fall off. If the plant has buds, and turning of the plant is desired for more even growth, then it should not be twisted more than 1/4 turn each time. 
WINTER: Tropical hibiscus can only withstand freezing temperatures for a very brief time before there is damage. In milder climates (USDA zones 9&10), if you can trap sufficient ground heat by covering your plants, you may be able to prevent freeze damage to plants in the ground.
PRUNING: It's best to prune when the tender new growth that results won't have near-freezing temperatures to contend with. Many will prune a third to a half of a plant at a time so that they will still get some blooms from the unpruned branches. Use sharp shears and prune just above an "eye."
HOW DO I GET A HIBISCUS TO BE BUSHY: By careful pruning and pinching back of new growth, you can shape your hibiscus. Some varieties make magnificent bushes and excellent hedges, while others may tend to be spindly. Each variety seems to have its own "personality."
HOW LONG DO FLOWERS LAST: If left on the plant or cut and brought inside (no water necessary), the blooms of most varieties last only a day. There are a few whose blooms look good after 2 or 3 days. When cooler weather slows the plants' processes, blooms do last longer than during the summer.