This issue is adressing a schefflera I've had for over a year. I had unwisely removed half a branch a year ago, and I wanted to get it growing again. So I cut it down to a bud, and even 6 months after, when the rest of the tree is growing, the bud didnt grow. So I thought maybe the bud is dead, so I cut it down AGAIN to a leaf. For unknown reasons, that leaf died, and then the stump turned black until it reached another leaf (so aprox 1/4 in of dead stump on end of branch). Now, the leaf that stopped the black dieback (the last leaf in the branch, too) is now dieing, and there are more buds that are dormant on the branch, but I only have a centimeter to work with, and I don't want them to turn black too. What is the best thing I can do at this point?