Hi there! Well, Plumeria like to go dormant for the winter and they don't like to be cold or have their roots stay wet for too long - so sometimes the reduced daylight / temps mixed with staying wet too long or getting too cold can make them rot. The bst thing is to let it dry out in between waterings and to have it in a really well draining soil so it doesn't stay wet as long. If you allow them to go dormant they need little or no water during this time.

Sometimes they can shrivel from not having enough water too. What is your watering schedule like? Is the soil wet to the touch right now?

I'm not sure there is anything you can do at this point depending on how much it has been affected, could you post a picture by chance? Does the soft area look dark? If it is truly rot then you will have to cut it to try to save it. Maybe others can chime in on this or we can get a little more info before telling you to cut though.

You could also take the plant out of the pot and examine the roots to see if they are brown and if so prune those off.

I have a small 8" plumeria that I bought from Hawaii in Dec 2011. Planted it and kept it indoors in part to protect it from the harsh summer of TX in the first year. It did awesome indoors, grew couple of inches and produced lots of leaves that fell and new ones came. It even flowered much to my surprise, a small infloresence about 5-6 flowers.

I kept it dry over the winter hoping to take it out this summer. But alas even with the little spraying of water the stem has gone soft and squishy. A small bottom portion is still hard. Should I cut it off?

I tried to dig it out and let dry for a day and then planted it again. The soil in the pot has very little moisture in it. Please advice!

elucas, thanks for the post I have cut off the end of a cutting I have been saving for a friend. Just recently it has been getting a little soft so I pulled it out and I see the end is brown and dried up with the "bark" coming off. So I cut back and will try to keep it drier until we get warmer weather. It had just started to get softer and I have never had this problem before maybe the soil has been too wet. The "bark" is showing some whiteish spots and this was starting to worry me. If it goes completely bad then I will just have to do one more cutting for my friend as he only has one white Plumeria and would enjoy my yellow flowers. It has been a blessing we have enjoyed from the wonderful blooms we get each year.