That's spider mite webbing.

No, I'm saying that the webbing on the very tip is from spider mites. It's not unusual for plumaria to suffer from this pest, which can weaken the plants if uncontrolled.

I am not saying that the mite infestation killed your plant; I doubt that that's the scenario at all. A containerized plant, stored in a dark garage for the winter, may be susceptible to root rot, for example.

You need to take a look at the growing conditions provided.....planting medium, watering, etc. How long have you had it, when was it last repotted?

You can use neem oil to treat the mites and then you will need to find how far the damage goes down and remove all the dead wood. Then clean your blade with bleach or alcohol and make on final cut just below the point. If you can place it on a heat pad to start warming it up then do so. IMO the best strategy is to jump start it from hibernation and get it growing. A growing plant walls off dead areas and can recover. Best of luck and hope it recovers.

thanks for all your help, I'm searching for heat pads and will start cutting tomorrow, will update with pics. The pics below are from last summer.

Hopefully it will recover for you. Best of luck.

Devin hope you write again about your plumeria. Hoping too that it recovers nicely for you once you get rid of the dead wood. You asked on the other thread about Maui Plumeria Gardens. I've obtained about 90% of my cuttings through Doug at MPG. Very nice man and he'll guide you through selection if you like. Take a look at their website and see what you think. The beauty is that you get a NOID with every cutting you order. Best to you.

Severe mite infestations, like yours, can contribute to or cause black tip. The tips are obviously showing black-tip necrosis and obviously showing the presence of mites. Mites will not feed on dead tips, so the mites were there before the tips died, and in my opinion could be one reason the tips died.

Is there any reason to suspect freeze damage? How cold did they experience?