Treeborn Frog
I think the name is confusing unless you have knowledge of the original name, which was Yomi Frog. Yomi refers to a concept in Japanese mythology that basically presents a mutual afterlife plane where spirits reside.
That being said, in regards to the English translation, I'm not sure why the name was picked to something so odd. While the card doesn't really seem to represent the traditional idea of Yomi very well, "Treeborn" is just straight up not a thing. Maybe the implication the English localization team was that the frog was coming to Earth from Heaven or something?
And then it finally hit me like a minute after writing all that. It's a pun on "reborn" and "tree frog". Which makes a lot more sense in context now, but I admittedly have been mulling over the meaning for multiple days now and it wasn't until someone explained the french name that it finally hit me.
