I'm an English-speaking South African, and although holly does not grow in my country, we still use it as a
Christmas decoration, usually complete with fake snow!
Holly is used as a name here; I have a step-niece with an Afrikaans father and an originally English mother, all now resident in the UK, named
Holly. Her parents are both deaf, her father profoundly so, and when naming their children they looked for names that he could say.
Holly's brother is
Fraser, a family name which their father can also manage. Other people use
Holly because they like it, but it's never really been common or popular.