Its a common early folk art motif. It shows up in every folk art book I have, not that I have a lot of them but variations of it are present in each one. I think its a sort of sub-theme on the "tree of life" motif and concept. Also seen often is a pot of flowers and pot of vines or a stylized mix of all of them. It also appears to be present in multiple types of folk art mediums and across different regions and cultures in early America.
