Two old/mature red Hibiscus, leaves look very healthy, but after moving them (in pots) from my mom's, they have never bloomed. They bloomed a lot before.
Hibiscus Plants Won’t Bloom
Certified GKH Gardening Expert
These plants can be somewhat tempermental. Most likely the lack of blooming is related to the change in its environment (temp fluctuations, light, etc.), resulting in stress. However, once the plant has accepted its new location and adjusted to the area, it should resume blooming. You can also add some bone meal to the soil to give the plant more phosphorus, which will help with blooming.