Hibiscus moscheutos is what is usually referred to as Hardy Hibiscus. It will hybridize with H. coccineus, H. grandiflorus, H. laevis, and H. dasycalyx, all members of Hibiscus section Muenchhusia.
http://garden.org/ideas/view/H...
It is also supposed to cross with H. mutabilis, (Hibiscus section Venusti) if H. mutabilis is used as the pod parent.
I have never heard of it crossing with H. aculeatus.
H. aculeatus is in Section Furcaria along with H. Acetoscella, H. cannabinus, H. fucellatus, H. radiatus and H. sabdariffa and could potentially cross with those.
