First of all, I would like to thank you for taking the time to read and possibly help me with my issues. I have had my largest plumeria since 2008 and the smaller ones came from the seeds that my mother purchased in the same year.
Now here are my issues. ALL of my plumerias were placed inside during the previous winters. This past one my largest and smallest was inside and my middle one (which came from my father-in-laws house) was in the outdoor building. However, the pot of the largest one would not drain completely. After the first of the year my husband and I emptied (what I thought) was all the standing water from the pot and he put it and the smallest one in our outdoor building with the middle-sized one. The plants were completely enclosed. After the majority of the cold weather went away we brought them out. I did a little looking around and my plants looked like they had root rot. So, I cut the ends off below the squishy part of the stem at a 45-degree angle so that no water could sit in the ends.
We did have two nights where the temperature went pretty low. So, I covered them with a blanket so that frost couldn't get to them (like I have always done in the past). Also, I drilled a bunch of new holes and ripped the bottom tray off the pot that they are in so that the water could get out and the soil could dry more. Water poured out by the way.
My questions are, have I killed my plants? What else should I do or is there anything else that I can do?