“But for their delight and use there were in Aman also a great multitude of creatures, without fear, of many kinds: animals or moving creatures, and plants that are steadfast. There, it is believed, were the counterparts of all the creatures that are or have been on Earth, and others also that were made for Aman only.” – ‘Aman’ in Myths Transformed; HoMe X: Morgoth’s Ring
so minor headcanon that since in Aman existed all species of animals and plants which were otherwise living in the rest of Arda (Earth), all of those “out of place” type plants, things which should have been “New World” plants or “Far East” plants but are nevertheless hanging out in Fantasy Europe, might have originally come back over with the exilic Noldor and spread. i’m talking about things like Sam Gamgee’s beloved taters, pipeweed (which is explicitly stated to be tobacco, common fandom jokes not withstanding); and perhaps cranberries, wild rice, sweet potatoes, maize/sweet corn, tulips, camellia sinensis aka the tea plant, sugarcane, cotton, etc.
basically, all those useful sorts of things which were in fact imported into europe by explorers in various time periods – except in this case some of them came with the Noldor from Aman. the ones which would in our world be native to the Americas, particularly. the others might have actually been transported north or west into Middle-earth from Harad and Rhûn, of course; or come into Valariandë/Beleriand with the first groups of Men or the later Easterlings.
