Jeremy,
Is this only on one branch? If so, I would prick the soft spot with a pin to see if latex leaks out. If latex leaks out, I would try a little water. If no latex, I would cut the branch below the soft spot until you reach clear, white wood and seal with latex caulk. If this is on all three branches, I would cut back all to white wood.

Frankly, I don't like the looks of the branch since the softness/wrinkling is confined to one area, rather than the entire branch looking somewhat dessicated.

Since this plant has such sentimental value, I would be aggressive in treating the plant. You don't want rot to progress all the way down the plant.
Mike

that's kinda what I was thinking. I don't know if it got too cold or what, but I'm going to cut it back to white wood tonight and get some fungicide on it. It's on all the branches, but luckily, it hasn't progressed down the "trunks"

Ok, so I got extreme and started cutting. My wife cried as she watched, I kinda hurt inside a little myself. One branch seemed to be completely white a little bit of the way down, the other I had to keep cutting, but finally got to where it had very little brown, only on one side. I'm wondering if that's ok or if I need to keep cutting. I dusted with cinnamon as a temporary until I can get some good fungicide. All I have at the house now is neem oil from my roses. I'll treat the cuts with a more potent fungicide tomorrow. Is the "lawn" type of Green Light fungicide what I'm looking for? I've been having bad luck finding any that I feel is sufficient without being overpowering. I'm going to water in the morning with SuperThrive and hope for the best.

As for the branch with a little brown still showing, should I cut it further? It's good and hard along the trunk where it's brown, so I'm hoping I don't need to cut if further.

In answer to your question I am reminded of the Clint Eastwood line. "Do you feel lucky?" If it were mine, I would continue cutting to white wood. Now, if that will leave practically no branch, and you are concerned about the resulting shape of the plumeria, you could decide to take a chance and leave it alone. You could also just cut out the brown area instead of cutting the entire thickness of the branch, spray it with fungicide, seal it with latex caulk, and hope for the best.

If you don't cut it, I would definitely get a good fungicide and watch the area closely for any sign of progression.

Let us know how it works out. Remember, if it starts to go south, you can always take a cutting of a healthy branch and root it.
Mike

I would definately cut out all the brown. Leaving any is taking a chance on losing even more of the plant. I had a Celedine cutting that looked just like your pics, except just above the soil line. I cut off all the shriveled/brown area and it seems to be doing fine now. Mine was only a single stalk cutting. I wish you the best with your tree.

John

I decided it wasn't worth the risk to keep the plant even, so I continued to cut about another 4 or 5 inches off of that branch till the inside was all white. I watered with SuperThrive this morning and I'm hoping for the best. Since it is so well established (no problems at all till now, and it's been almost 4 years), I'm hopeful that it's got the strength to pull through. It's out on the front porch now where it'll get some good sun and enjoy the 70 degree day we have ahead of us. I'll let you all know when it starts sprouting new claws. Hopefully it won't take long because the anticipation will kill us.

Jeremy,
I'm assuming the cut branch is still more than about 3-4" long. Shorter than that it may degenerate and not sprout new growth.

It takes a little bit for the plant to develop new growth from the cut end. Watch for swelling at old leaf scars and the emergence of tiny leaves. Those are the start of new branches. Don't get discouraged if they form and then regress. Sometimes you will get several new branch "buds" and some will progress while others regress. Treat the plant normally, i.e., be careful of watering when there are no leaves. Fertilize normally for a awakening plumeria.

It should do well.
Mike

Thanks for the encouragement. The branches are still pretty long, just not 4 feet tall like they were before. I'm hopeful.