Whenever anyone discusses rooting any plant in water I highly, highly recommend changing the water frequently--at least once a day and optimally twice a day. Roots need access to air and I have seen success rates drastically improve when cuttings were given access to fresh, oxygenated water. Most of the time the rotting occurs because the tissue suffocates and dies. I would even go so far as to suggest an aquarium bubbler be hooked up for a low-maintenance approach, but I personally have not tried this. Only takes an air pump, stone, tubing, and let's say a water bottle or 2-liter bottle. Only an idea in my head. Wish you the best though!