i had gotten one last spring
when i went to put it in ground, i looked at the root system
the roots were very fine and very close to the surface.
i knew with this hot weather we get, i would have water issues.
i mulch the hell out of it.
Usually, people say keep the mulch away from the trunk
i have a hard time doing that with the amount of mulch i use.
My understanding and also experience,
indicates that some species are much more susceptible
to fungal issues on the trunk than others.
i am pretty sure my CORG was taken from a cutting or air-layer,
so i figured mulch touching the trunk shouldnt hurt it
and so far it has not.
the kiddie pool doesnt sound like a bad idea.
i have a 5gal buckets for a few plants, and when i put drainage holes,
i would put them about an inch above the bottom, and use some lava rock at the bottom,
so there is a reservoir that can be used to keep the soil moist.
Some kind of screen (a type of false bottom) ,
would not be a bad idea on top an inch or so of lava rocks.