how do I make hibiscus bloom, no more nitrogen please, the green growth is 10 to 1 now. I want to force the hibiscus to bloom. I tried some bloom fertilizer, however, they are acting like the nitrogen is dominant, all green and no blooms. I have heard of bone meal and epsom salt to force bloom, also phosphates or phosphorus .......anyone? btw...... these are in-ground plants and always have been, zone 9/10 Florida.
Force Bloom Hibiscus Plants
Certified GKH Gardening Expert
This could, very well, be due to there being too much nitrogen in the soil. Make sure the container, or area is well draining and flush with extra water, being sure that they do not sit in water. Adding a fertilizer with, both potassium and phosphorus can help in some cases. There is a product called tomato set spray that you can get to enhance flowering but it is somewhat toxic so you would have to make sure you wash you hands. It won't last on the plants very long, but it will increase the number of blooms. I have often found that potassium oxide, which you can get at many websites, will stimulate VERY fast plant growth and flowering at the cost of being somewhat expensive.
Here is a link some articles of all of the information you could need for the hibiscus: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/