You say that this Hibiscus is 30 years old, has it never produced seed? If it has always dropped it's pods after blooming then it probably always will. Hibiscus are hybrids and many will just not produce seeds. One possibility is that it is self-sterile and can not fertilize itself. If their were other Hibiscus around it may be possible to pollinate it with a different Hibiscus, but there is no guarantee.
