I think hibiscus wants full sun to be really happy. And it will get attacked by midge gall, a small fly that lays it's eggs in the buds and causes them to turn yellow and drop before opening. If you treat them with Bayers tree and shrub you can prevent this, but it's not cheap. I love the flowers, so it's worth it to me. :o)

The one in the pic gets morning and he afternoon sun there it one next to it in the shade here that's gets morning sun. I'lll see how it goes