The cutting being trimmed just below a leaf axil. This is important, as apart from helping the cutting to root, it is also at this point that the new tubers will form at the base of the new plant. In this area of the leaf joint, the leaf axils contain the ability to form eyes in the tuber, which are essential for the growth of shoots the following year. If new eyes are not formed in the tuber, it can become blind and fail to sprout the next time.