Yes, ethnic enclaves. Being married to a Filipina, I know that Filipino families (as well as mixed, like us) want their kids to be at least bilingual (Tagalog and English). English to make coping in our society easier, but Tagalog to hold their heritage.

And, yet, our society absorbs elements of their culture. In addition to your examples of Xmas trees, we have St Patrick's Day (Irish) and Cinco de Mayo (Mexican). In the Southwest, Hispanic culture is everywhere. I can't speak for places like Seattle (where Dope lives). But here, there are not-Taco-Bell Mexican restaurants everywhere, groceries routinely stock a plethora of chiles (serranos, guajillos, etc), Cinco de Mayo and Dia de los Muertos are moderately "big" here, etc. And it helps to speak a little Spanish if you live here.