I have this Stewartia Pseudocamellia and Japanese Umbrella Tree, and want to transplant each of them into the pot seen next to it.
Questions -
When, or under what conditions is it appropriate to transplant them?
What about pruning - I think the Stewartia is about as large as is appropriate for the space. When, or under what conditions is it appropriate to prune them?
The roots for both are quite pot-bound - should I prune the roots? If so, can you suggest a good resource for learning about root-pruning?
What do you recommend for the soil in the new pots?

Thank you for looking - I welcome any and all comments!

If the plants are not going to be planted in the ground you do not need to trim the roots. If you want to you can remove about 2" around the sides and off the bottom and plant in any good potting soil. You can do the Pine any time from now until March if you root-prune or any time at all if you don't. I would wait to do any pruning, branch or root, until late winter or early spring.
One thing to note is that you will have to break the pot the Stewartia is in to get it out and do the same if you ever want to transplant the Umbrella Pine from that new pot. Both are narrower at the top than in the middle.

CalPolygardener said: If the plants are not going to be planted in the ground you do not need to trim the roots. If you want to you can remove about 2" around the sides and off the bottom and plant in any good potting soil. You can do the Pine any time from now until March if you root-prune or any time at all if you don't. I would wait to do any pruning, branch or root, until late winter or early spring.
One thing to note is that you will have to break the pot the Stewartia is in to get it out and do the same if you ever want to transplant the Umbrella Pine from that new pot. Both are narrower at the top than in the middle.

Thank you! That's all helpful to this uneducated gardener! I was aware of the ceramic pot issue - it is actually already sliced up (with a diamond blade/grinder) for easy tree removal. I'm hoping to re-assemble the pot, and maybe add a colorful grout accent lines!

Sounds cool!