All About Gardening
Hibiscus is happiest in soil that is well-draining but will hold a consistent amount of moisture with regular watering.
The range is between 6.5-6.8. Acidity in the soil is good for most plants. It causes the nutrients they need from the soil to break down in a way that is most available for use.
While they will grow and produce some flowers in partial shade, they will produce far more blooms if they are in full sun!
Hibiscus plants are water lovers, so whether by rainfall or by irrigation, keep the soil moist, but don’t flood the plant.
Adding mulch will hinder the loss of moisture in the soil. When planted outdoors, 3 inches should be enough. Use 1 inch for container plantings.