First of all, a photo is always helpful...Also you need to cut back any rot back to healthy green tissue, or it will spread. Also cut back all rotted roots. When you repotted, did you check the roots for rot? Cactus soil tends to be too peaty, which is not good for drainage. If you cut it with 50% perlite, it would be better. If the roots are rotten, and there are some healthy stem sections you can cut them and root them after they callus over.

Christopher

Thanks! Here are some photos of the plant. The whole pot used to be full with stems about 2 months ago. So the roots didn't seem rotten when I re-potted it, here you can see a photo of what the stems look like, it's actually those that seem more rotten, very squishy and brown on the inside. I can get some perlite and re-pot that, and inspect the roots a little better.

Although if the stems are rotten is it a goner?

Here is a photo of one of the stems still in the pot that I trimmed (all it's leaves had fallen off). This is what the stems I pulled out looked like when I re-potted.

If all the bottoms of the stems are like that, it is root rot. Your only option then would be to take cuttings of healthy upper stems that are still green inside, before rot spreads up the stem. And it appears you have some healthy stems from the photo.

Overwatering in a peaty mix like that is death to the plant. Also I would use an unglazed clay pot, which will dry out the medium more quickly. If you use an organic mix like that, even with added perlite, I would use a smaller pot.

If you do take cuttings, let the cut ends heal over before potting, and then, do not water until you see roots. No roots, no water.

Christopher

Awesome thank you very much for the advice. The pot is definitely too big now that 3/4 of the plant has died!

How will I know when the roots start to grow after it's potted? Do I just occasionally tug on the stem to see it it's resisting? I've tried to propagate a much smaller (but healthy) jade and nothing really happens, the cuttings stay healthy but just sit on the surface and don't root - I've read I should get rooting hormone.

I used to have no luck at propagating jades. In fact, I've been known as a jade killer. Finding this forum and the great advice of the members has changed that. Finding the gritty mix was the biggie for me.

The plant on the left is a newer piece. A little tug tells me it has rooted. And it is getting new leaves. The plant on the right was the same size last summer. I don't think I used rooting hormone, but I did let it callus a couple of days. These are in 2 inch pots.

Wow that is gritty mix! So it looks like I definitely have some replacing to do on my soil this weekend. Hopefully that will help it come back to life!