Hibiscus plant won’t bloom
Hard freeze last year and they both suffered from the freeze but recovered quite nicely. What would make the one plant stop blooming? They're fertilized every 2 weeks.
To much fertilizer is likely cause.
To much Nitrogen will cause lush green plants and no blossoms.
You can add Phosphorous with Bone Meal fertilizer.
Here are a few links for you with more information.