Where did the “picking flowers” euphemism for “answering the call of nature” come from? Although, saying it like that makes it sound a bit obvious…3

I first saw it in SCP-6385:

pick flowers (a colloquial idol term for urination or defecation)

And then checking Google, the only easy source I can find is Urban Dictionary 2020. Is it just something that came up in the last few years? Was it actually imported from Japan?? I assume that’s just SCP Worldbuilding, and not really what happened.