Wondering if someone can solve this problem my brother and i are having in with hibiscus plants?

I have 8 rose of sharon trees planted in the grown been there for years and bloom late summer beauty flowers that look like hibiscus flowers. I have been told that my rose of sharon bushes are called hibiscus. I also have 2 hibiscus bushes in planters on my porch they have darker green leaves shiny and beauty flowers also as a hibiscus has. I know that these bushes are tropical and have to be pulled inside early fall. My problem is my brother disagrees with me that the ones planted in the yard are hibiscuses like i was told. I looked it up and Im trying to figure it out and I think the rose of sharon trees are from the same family of the hibiscus and there not tropical. He has the same ones I do I told him there rose of sharon hibiscus and are not the tropical kind he also has the darker green leaf ones in pots and brings those in and also the rose of sharon ones that he says are not and brings them all inside...he says they all will die if you dont ....i dont agree with him

Wondering if someone can solve this problem my brother and i are having in with hibiscus plants?
Rose of Sharon is indeed a Hibiscus, hibiscus syriacus. They are deciduous and tolerate alot colder climates than the evergreen tropical types (hibiscus rosa-sinensis) these will only grow in zones 9-11 whereas the syriacus will tolerate zones 5-9. Mine take temperatures down to 20 deg F no problems. Hope this solves your argument.
Reply:Everybody is right, except the hardy kind needs no mulch. Mine is 5 years old, 8' tall, and has 25 stalks. It's never been mulched. I'm in NW OH, and the weather is really cold.
Reply:Rose of Sharon are hearty and can stay out side, they are also in the hibiscus family. There are Hibiscus that can be left outside as well and they must be cut back and mulched with at least 12 inches of mulch every year, the tropical ones you must bring in for the winter....the ones that can be left outsided should have been labeled as hardy hibiscus when they were purchased.
Reply:They are part of the same family. Rose of sharon stays outside and comes back every year. Some hibiscus, like the hardy variety can stay outdoors too. It's the tropical variety that comes inside.
Reply:You are right! The hardy hibiscus (Hibiscus syriacus) is also known by the names Althea and Rose of Sharon. The tropical one (Hibiscus rosa-sinensis) would only thrive unprotected in Florida, Hawaii, somewhere like that. You got the key ID right on-the shiny leaves of the tropical one! Hurray, you win!