Hi I'm new here and in need of some help. I have two yr old plumeria plants. They flowered last year and I overwintered them in a greenhouse. We had a problem with the heaters and they got a bit of a freeze. The leaves dropped and the tips of the branch(s)froze. The remainder of the stems seemed fine as did the roots. I cut off the damamged tips and now have them outside. There's been no leaf growth yet but it's still fairly cool here at night. The tops of the stems are drying and black. I've cut them back to healthy tissue but the tips continue to dry and it's not like a callous. I've had plants develop stem rot in the past but it had started at the base and they died quickly. One of the plants looks like there's some growth below the damage but I'm afraid that the problem will continue to move down the stem. Is this rot? Can these plants be salvaged? Does anyone have any suggestions of what I can do? Thanks