My zamioculca stem just broke off at the roots, the bottom is black but the rest of it looks healthy.
I touched the stem of the plant and carried it in my hand. the base was rotten but the earth doesn't seem wet.
Here are some photos of how it looks:
How should I treat this? Are the other stems at risk?
There was a previous question on Zamioculcas that might be of use to you as you explore reasons for this. Images of good solid plants show light colours in the root (Google images search). I think standard practice in this situation would be to pull the plant from the pot and inspect thoroughly for signs of excess water, soft tissues and so on. Treat it as a division and repotting exercise, pulling apart into sections with root, tuber and shoot and replanting in known fresh soil, discarding anything that looks suspicious or feels soft. You can quickly find recommendations on a mix that would be suitable for this plant.
