The "Green Grow the (fill in botanical phenomenon of your choice)" explanation has the aura of a bunch of people sitting around over beer and speculating about where the word came from. Eventually they all agree on one possible expanation that sounds reasonable. Then later, one of the imbibers quotes the speculation as fact and it since it does sound reasonable, everybody accepts it as the official explanation. Lots of misinformation gets manufactured that way. I go with the link Dicho posted.