I went on Google Books and found a n extract in Werner's anthogyof Readings and Recitations no15, 1896. J Hooker hamersley wrote a poem Yellow Roses.

'Of rich yellow roses a cluster he sent in the long ago --- in the long ago. A wee dainty note in its heart lay hid ,'mong the buds concealed like a fairy sprite ..... etc (yukky)

Not the song we are investigating but that shows it wasn't an American Civil War song.


More a 'generic' anti war song , maybe by T Peacock?


In the 60s there were quite a few like Universal Soldier by Buffy St Marie / Donovan, Phil Ochs, Dylan , Where have all the flowers gone and so on.


There is still no connection with a Spanish poem, translated and then set to music.