Question
Dear John,

My Yucca houseplant appears to have a rotting stem. The plant consists of one long branch (I guess you'd call it) coming form the roots. The branch is around 3 feet long and curls round the pot rather than vertical.

The stem immediately below the leaves at the end of the branch became very thin and fell off about 6 weeks ago. Since then, the stem has started to rot with a strong smell of decomposition. It is working it's way back along the branch and so far I have removed just over a foot of decayed stem.  The stem becomes very mushy to the touch and eventually it is clear that the material within has shrunk away.

Is there anything I can do to stop the rot?

Thank you very much for any advice you are able to suggest.

Regards,
Martin.

Answer
Hi Martin,

If I understand your problem, you are trying to save the remaining root system of the plant.   First, stop watering the plant.  Remove any stem that appears discolored.  Normal stem tissue will have an off white appearance with a definite "core" surrounded by several rings of various conductive tissues.  When you remove the rotting stem, make sure to disinfest your cutting blade (rinse in 10% bleach) on subsequent cuts because your knife blade may contain bacterial cells.  

The goal here is to cut enough stem away that only healthy stem remains.  It is sometimes impossible to do.  You may take drastic measures and remove the stem to within a couple inches of the soil.

It is worth a try.