Hibiscus plant leaves turn yellow (Southern California location)

Question

Flowers are sometimes “deformed”

Answer 1

There are many things that can cause yellow leaves, unfortunately. Some dropping of older, yellow leaves is normal. If it's moving up the shrub, it can be problematic. The deformed flowers happen often and these abnormalities are called "sports." Many factors play into that phenomenom so it's impossible to determine why.

This article may help: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm