the white stuff could be "white fly".5 P8 z3 r. H4 N7 j7 P4 q: C
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.1 J4 J: W/ O& p( U( D! @
Hibiscus is a typical plant, show helps a lot.