the white stuff could be "white fly"./ J `% \& r( M! c* i r6 ]
I had the same problem before. It because your plant is too wet. I showed the leaves twice a day for a whole week, then the white filies were all gone. 9 Y* N7 n8 j& w% _; Y: ~3 {6 H" FHibiscus is a typical plant, show helps a lot.