Well, I want to grow some comfrey, but I just can't figure out the difference in the varieties. Looking up info on the web seems to take you back to the same article, no matter where you look! I'm pretty sure I don't want Bocking 14, because of the higher toxicity levels. Plus, I think its weird to grow a plant that has been sterilized. But I do want to a comfrey that will benefit the compost pile! If bocking 14 the only one that has worthwhile nutrient levels ?