I have a 13″ high new hibiscus plant. Has not bloomed yet. Lots of dark green leaves. Have had it about two weeks. It gets sun all day. Have had 90 – 100° weather for the past few days. I keep soil moist at all times. It has not bloomed yet. Would like to know why.
It likely needs some more fertilizer, especially phosphorus which helps with blooming. Use a "bloom booster" fertilizer or add some bone meal to the soil to help add some phosphorus. Here is more information: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm