I have several young trees I grafted this spring, currently in 1 gallon pots in my yard. I went out to adjust them yesterday because of a summer storm and I was shocked to discover that at least one of these babies has extended its roots into the ground beneath the pot. This surprised me for two reasons: I didn't expect the roots to fill the pot so fast (the rootstock seedlings were in their propagation tray for about 1 year and only moved up to the 1 gallon pot this winter), and the pots are on rock xeriscaping, not bare earth. Nevertheless, this happened. I have 5 gallon pots to move these into (some of them are starting to blow over in their 1 gallon pots). My question is, should I cut those earthen roots now, while it is 115F in Phoenix, or wait? Normally I would say wait, but it seems the bigger pot size might be beneficial, and I'm planning to move. I don't have a move date yet, but it could very well be within the next few months before the temps have really cooled here, and that would allow the earthen roots to be even more established when I cut them.
What do you think, cut them ASAP and provide shade, or wait as long as I can and hope temps cool significantly but the roots are more established in the earth?
These pictures are probably two months old, but give a general idea.