what did he eat?

by carly
(chicago illinois us)

so i was letting my russian box tortoise run around in the back yard while i was reading then i noticed that he was eating a leaf im not sure what it was but i attached a picture, i also saw that he had eaten a bit (couple bites) of a hosta im from the chicago area and i was just wondering if i should be concerned ( the leaf he ate was bright green on the front and kind of white and fuzzy (like suede) on the back