Just some mumblings for some JM I have in containers and my observations In dirt.....roots go as horizontal as they need, staying up high as that is where Air is normally is....close to the surface In a pot, IME, roots tend to gravitate towards the sides and then down. I suppose mainly as that is where there is more free air. Potting Medium + Drainage Holes is key for containers....I think Drainage holes being the most important factor given my statement in how IME, I see how roots grow. Not pot bound but does anyone develop roots by removing them yearly when young and then root prune to promote a denser rootball. I don't grow in smaller + 1 upsize pots. I have #3 in #15 sized pots, #5 into #25 pots, etc. I did that to to a #10 which filled a #30 in 2 years. There was maybe a inch left before it hit the sidewall.
