Why do so many buds on my hibiscus fall off?
I live in Hawaii. The hibiscus plants are in large pots. There are no pests evident on the buds or leaves but a lot of buds turn yellow and fall off before opening.
Certified GKH Gardening Expert
This can have a few causes.
The most common is lack of nutrients, or the wrong kind of nutrients. Too much nitrogen, or not enough phosphorus and potassium will cause bloom drop. You can offset by adding nutrients high in phosphorus and potassium, and continue with a high nitrogen feed during growing season when it is not blooming.
Another cause is not enough sun. They will grow very bushy in partial shade, but will not flower as well. They prefer full sun for proper bloom-set.
These articles will help: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/hibiscus-fertilizing.htm