Wither Bonemeal

 I'm not sure just how much this would add to the game, or the experience, but something I've long considered is the idea of Wither Skeletons dropping withered bones, which could be used to create a wither bonemeal. Only with this could you grow Nether foliage and speed up the growth of nether warts (since regular bonemeal doesn't work on nether warts). In fact, if this idea doesn't really seem that great, then I'd just be happy with the ability to use regular bonemeal on nether warts, ha. That was the whole genesis of this idea, and making it be able to (exclusively) grow nether foliage as well was just something I threw in there to justify it existing more. Please give your thoughts!

Edit: If this idea still seems a little boring, I have come up with yet another functionality! What if using this item on tree saplings would halt their growth? Mapmakers are already blessed with a myriad of flora to decorate with, and having saplings that don't grow to add to the garden would be swell!