My yellow flowering hibiscus looks healthy and is blooming nicely, but I am concerned that it continually has several leaves that yellow and fall off even though most of the leaves are dark green and appear healthy.
Hibiscus Yellowing Leaves
Certified GKH Gardening Expert
Some leaf loss is normal for a hibiscus as long as it looks healthy overall. You can reduce it a bit more by giving it some fertilizer and increasing watering for the plant.
Leafy plants naturally discard the oldest leaves so a few yellow leaves on a hibiscus is natural. The plant is simply making room for the new growth. I pick two or three yellowing leaves off my hibiscus every other day. I have a lantana that has the same habit.