I've been learning there are lots of greens we toss in North America, but could consume. A friend said in Vietnam, she ate amaranth leaves growing up. We love fiddleheads in Eastern Canada (the young tops of Ostrich ferns). Since they are a bit bitter, we often add a splash of vinegar (I like balsamic). I wonder if the acid alters oxalates? I have just eaten broccoli leaves (steamed). After a few rounds of frost they are lovely sweet.