If the 2 are crossed, are the offspring hardy or more tropical?
Hardy x Tropical hibiscus
I am not sure if they can be crossed. They are two different species I believe. But maybe possible under certain scenarios and gene transplants. Nowadays, we are acting like God :)
I thought they could be to produce new colors?
I've never heard of anyone successfully crossing those two species. The genetic differences are too great.
Some of the "tropical" species can be crossed - schizopetalus, Andersonii, rosa-sinensis, etc.
Barb