Is Black Oil Sunflower a hybrid or an heirloom? I realize that this sounds a bit silly to ask, but try as I might, I can't find the answer anywhere on the internet. I know sometimes (rare) the seed falls from a birdfeeder and forms a plant. Those plants don't seem to do to well, though. I also know that the hull's of BOSS have a chemical in them that prohibits plants from growing, much like walnuts hulls do. Not sure if the plants are hurt by this or by the result of being hybrid.