Plant in spring, summer, or fall, spacing plants 3 to 6 feet apart. Dig a hole only as deep as the root ball and 2 to 3 times as wide. If your soil is in very poor condition, amend the soil you’ve removed from the hole with a small amount of compost. Otherwise don’t amend it at all. Carefully remove the plant from the container and set it in the hole. Fill the hole half full with soil, then water it well to settle the soil and eliminate air pockets. Let the water drain, then fill the remainder of hole with soil and water thoroughly.
Hibiscus require at least 1 inch of rain (or equivalent watering) each week. They like to be constantly moist, but not wet. Feed twice a month during the growing season and prune as necessary to control plant size and cut back errant branches. Cut branches back to just above a side shoot. Hibiscus are sensitive to cold and should be protected when temperatures dip into the 30s; container-grown plants should be brought indoors. Check plants periodically for pests such as aphids, white flies, and mealybugs. Use a horticultural oil or insecticidal soap to control these pests.
When hibiscus are in their blooming stage, they require large amounts of water. Your hibiscus will need daily watering in warm weather. But once the weather cools, your hibiscus needs far less water, and too much water can kill it. In the winter, water your hibiscus only when the soil is dry to the touch.
A growing hibiscus plant needs lots of nutrients in order to bloom well. In the summer, use a high potassium fertilizer. You can either use a diluted liquid fertilizer one a week, a slow release fertilizer once a month or you can add a high potassium compost to the soil. In the winter, you do not need to fertilize at all.