Although rhubarb pie is delicious, the leaves are poisonous. They contain oxalic acid, which can make you sick and enough of it will kill you. In fact, the amount necessary to kill a person has been carefully calculated at about eleven pounds of leaves for a 150 pound person. That seems like way more that anybody would ever eat, so I doubt that anyone has ever died from eating rhubarb leaves. However, a smaller amount would certainly make you very sick.
Rhubarb originated in China and made its way across Europe and eventually to America. It’s more of a cooler climate plant. It’s a perennial that needs a good dormant season so that it can burst forth in the springtime.
So, why is it in this blog? A lot of garden plants escape and can be found in the wild, at least for a while, and so they are included in the field guides.