It’s a shame I’m just learning this now. I could have sent cards to my mother and grandmother (though technically speaking, she’s not the Scottish one).
Apparently, April 6 is National Tartan Day in the US. It is designed to celebrate the role the Scottish immigrants and their descendants have played in the shaping of America.
Anyway, you can read more about it on the official website.
Autobiographical note: I’ve just now learned the motto of my mother’s family…it’s In Ardua Tendit, meaning “he has attempted difficult things.” I find that wildly appropriate for that side of my family.