I now see how widely divided we are! Moss roses are succulent plants that CA uses to line the inclines of the CA freeways, especially in moist climates along the coast.
Those are either roses of Sharon or wild roses, but they are not moss roses. Sorry, NC...
That collection of all the worlds knowledge also called Wikipedia says "Rose of Sharon is a common name that has been applied to several different species of flowering plants that are valued in different parts of the world. It is also a biblical expression, though the identity of the plant referred to is also unclear, and is disputed by biblical scholars. In neither case does it refer to actual roses, although one of the species it refers to in modern usage is a member of Rosaceae."
Unfortunately, in typical Wikipedia fashon, they don't tell us what member of the rose family the term refers to...