Lovely quote, attribution likely apocryphal (and I don't think it was a poem). https://quoteinvestigator.com/2012/06/ https://quoteinvestigator.com/2012/06/ is

Lovely quote, attribution likely apocryphal (and I don't think it was a poem). https://quoteinvestigator.com/2012/06/ https://quoteinvestigator.com/2012/06/ is a nice writeup (assuming you trust its citations).