Answer: All hibiscus have yellow leaves now and then. A few yellow leaves usually only mean that those leaves are getting old and need replacing. If your plant has many yellow leaves it is stressed. The most common causes of plant stress are under-watering, drastic environmental changes or pest invasions, especially spider mites. Sometimes the soil can be extremely alkaline and even if you fertilize regularly, your hibiscus can show signs of chlorosis. Iron applications can help the existing leaves green up and the new leaves come out green.
Hope this information helps you determine the cause of the yellowing foliage.
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