Q.hibiscus leaves are turning yellow
My hibiscus leaves are turning yellow…too much or too little water? Leaves continue to turn yellow.

Yellowing leaves is usually an indication of either, to much or to little.
Check the soil moisture before watering. The top inch or so should dry out.
Then water throughly. Make sure the pot is draining well.
When temperatures rise to 85 degrees or higher you may need to water twice a day.
Check for insects or disease, as this also can cause yellowing dropping leaves.
Treat with Neem Oil if your leaves are infected or sticky.
Here are a few links for you with more information.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm