How to remove sticky residue on plants?

[Qldgarden]

 

 

This sticky white 'stuff' is on some plants but the worst is on  the hibiscus. Three hibiscus get full sun and two others are in shade in the afternoon, but still get the heat.  The worst affected is in the full sun.  I have tried spraying white oil, rose spray, neem spray and the mixture of water and hydrogen peroxide.  The more I spray the more this 'stuff' seems to multiply.  Also hosing it off, which is great, but it evenutally comes back