Why do my Hibiscus buds fall off just before blooming?
The plant and buds look just fine and at about the time the bud should open, it falls off. I have had only about 8 - 10 blooms and about 25 to 30 buds fall off.
Certified GKH Gardening Expert
This article may offer some suggestions: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-flowers-hibiscus-blossoms-falling-off-plant.htm