- Take them out of the pot, or you'll bust it.
Bust what? The tree or the pot? I never take my trees out of their pots, except when I'm repotting.
leave them in the pot, but make sure you've got good draining soil
Yep, that's the standard for all cases and all seasons.
put them in the ground, then mulch
You can do that.
put them on concrete, then mulch
Seems less useful, but yeah, why not.
put them in a greenhouse
Only if it's a cold one
put them in a garage
Yes, sure, but I would only consider that for deciduous trees.
I see beautiful images of Walter Pall's trees, in their pots, on their viewing pedestals, buried in snow.
Of course, why not? Snow is a great insulator.
What's the consensus? Is it like soil mixtures, where everyone's method is different, and if it works it works?
The consensus is that soil needs to be free draining. The rest depends on your local climate and the type of trees you have. All my trees will be outside always, in their pots, without extra protection. This year I'll make an exception, for the first time, for a juniper that's not doing too well - I'll put it on the ground as soon as it starts freezing.
Note that I'm in the Netherlands, we don't have very cold winters, normally.
