Nick, Sounds like you are doing everything right. Is the organic mulch you mention placed on top of the soil or mixed in with the cactus mix, potting soil, and perlite? If so, it may be retaining too much moisture for that plant. I would try removing it. Conversely, I have had rooted plants become soft and sometimes wrinkle when they actually needed water. After I watered them, they firmed up in a day or two. I, too, thought I had stem rot, but they are growing nicely now. Some AZ people use shade cloth to filter the sunlight, but others don't and both seem to be successful. It might be sunburn, so you may want to shield those plants, or move them to more indirect sunlight. One person told me to use a needle to poke a small hole where the plumie was shriveled to see if latex oozed out. I tried that on several plants and all oozed latex. Only one of those eventually had stem rot, so it may be a good test, but I don't have enough experience to confirm it. Good luck, Mike

Hi bean-sprout. I had that problem with the wrinkled stem quite a few months ago and posted a note here. The popular vote was basically it was thirsty. I had one recently that I noticed was getting a wrinkled stem too, so I watered it, and it's starting to look better. I think the once a month thing during dormancy sounds like a good plan. I've also read that in the spring it's good to give them a good healthy watering with superthrive. Good luck on that and keep us posted. I'm sure you'll get a few more suggestions. Lauri

Looks like a very bad sunburn. Only way to save it will be to cut off the green part and attempt to root it. Also look and see if the root ball is still viable and if you can leave that in ground to see if it may recover from the roots up as well. It is possible the ceramic pot focused sunlight onto the stem and cooked it. Sorry it happened.

Glad they are helpful. I did not have any coir and I always use potting soil mixed with a lot of perlite for rooting plumeria, so I kept to that. I opened a new bag of potting soil and that had all the moisture needed. I did not add any water at all. I read this tip about usung a newly opened bag of soil somewhere. It works because I can see the droplets of moisture in my baggies. Another tip I read was to keep the ziplock of the baggie sealed and cut one of the perpendicular edges off, and open the baggie to plant by that cut edge. This way the baggie will fall off when you remove the tape, without disturbing any roots.