Question
Hello,
I'm familiar with general info on repotting/propagating, but hope you can offer some specific help!
1) A 20+ year-old barrel-type (spherical) cactus growing indoors is too big for the pot and leaning severely. I removed it to repot into an azalea pot of appropriate diameter, but was surprised to find such as large deep root system which also leans -- a large nodule (that presumably swells with water intake), with dozens of roots hanging off.  Do I have to find a pot to accomodate this large root system and also find a way to prevent future leaning...or (this is the real question) can I cut off this root system, let it harden off, then re-root it?  How likely would I be to kill the plant?
2) Similar question for a tall spiny cactus (unknown type) -- I was just going to repot it, but its root system is huge -- can I cut the plant in half and re-root it?

My gut says in both cases this is a bad idea.  I did this with a Jade (no problem) and Euphorbia (still awaiting results of success)...but since those are succulents that may be a different story.
Thank you so much for any advice you can offer!
Chris

Answer
Dear Chris,

All repotting with plants of that size might be better left off until springtime, when the plants are in active growth. I am not saying that you will kill the plants if you did so now, but they would grow more quickly if you postponed it until then, when higher ambient temperatures and bottom warmth are more available. It's not a problem trimming roots, even to the extent you suggest, but the plants will grow faster with more of their root ball intact. The leaning may be caused by it growing towards the light, but it also could be natural for the particular species to lean.

You can cut the plant in half and reroot, but it's best done in spring, for the reasons cited above.

Hope this is helpful to you.

Kind regards,

Jeff