The hibiscus keeps losing the buds before they bloom.
The Hibiscus Keeps Losing the Buds Before They Bloom
Certified GKH Gardening Expert
It could be from any number of insects, but thrips or gall midge are most common pests that affect the buds. These articles may help: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-flowers-hibiscus-blossoms-falling-off-plant.htm