Phil- Thanks for the quick response. I love The Trees They Do Grow High. One variant seems imply that the young man dies in battle but the rest are fairly ambiguous lyrically, as far as I can tell. There's speculation that the song might have been based on the 17th c. marriage of Elizabeth Innes to Lord Craighton, who died shortly after, but I've been unable to identify what he died of. Most of the sources I'm seeing just rehash the same scanty information.

Jeri- Yes, several threads.

Jim- Yeah, even if they are all anti-plague herbs (and I'm sure they were), they've just got too many other aspects in common for me to interpret the song that way.

Swaleman- Informative indeed, thanks.

Paul B.- Thanks! I'd completely failed to find this one, it's perfect.

Jack- True, but the plague itself continued to strike each ensuing generation for centuries after the Black Death, so I am optimistic. I'll also settle for non-ballads. The cholera epidemic is fascinating, thank you.