Hibiscus Plants Not Flowering Well

Question

Our two hibiscus – both around 15 years old, one is a single pink flower, the other is a double red – have been prolific flower-bearers every year. However, this year both have been extremely slow in producing with very few flowers at all. They have been pruned right back each winter and are well fed and well watered regularly. The leaf growth remains lush and green and both bushes appear quite healthy, but very sparse in flower production. What are we doing wrong? Would greatly appreciate any advice.

Answer 1

They likely need some more fertilizer, especially phosphorus which helps promote 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