How do you decide when to transplant a potted Palmatum to a field location, is it caliber, age and or is it the size of the root ball, or does it not matter at all?
The season matters, very much. Transplanting anything (especially deciduous) except an indoor-growing tropical should really be done only in early spring. Mid summer is the worst time, though if you are just dig a wide rootball, moving it quickly to a place with at least filtered sun, if not light shade, that has fast draining gritty soil, and you keep it well watered for a while, you may get away with it during mid-late August, but it's up to you, of course.
I am sorry but that is not what I am asking, I know you only plant trees in my location in the Fall or Winter, if in the season to plant, should you leave it it potted, if it is not big enough? So how do you determine when if it is big enough, to stand alone in a field, is it caliber, age and or is it the size of the root ball, or does it not matter at all?
To me it does not matter at all. And, I move potted maples to a field location any time of the year as I desire (in this part of the world the ground never freezes) Gomero