I have a florist rose that's been in a glass of water for maybe 6 months now. The bloom faded but it started growing leaves so i cut the bloom off and left it in the water. It now has buds of roots on the bottom and still has leaves growing. Should I leave it in the water until roots grow and then pot it up or should I pot it now? It is starting to get black spots on the stem. Should I use regular potting soil or seed starting mix, sand?