I've had good success with fall planting of apples. I think it helps to get the roots settled in over the winter before the tree comes out of dormancy the next spring.
I'm a big fan of late fall planting. Gives the tree a little more time for the roots to get established before summer arrives. I've also had good luck with winter planting of bare root trees.
Here in Oklahoma late August and early September can still be very hot. Late September through October is a good time for my area. I hate planting after Oct 1 though bc it's deer season so i try to get my trees in the 2nd and 3rd week of September. If I don't make it then I just left them go dormant and plant after deer season.
Potted trees could be planted at any time if you can provide ample water. Bare root due better in warmer zones when fall planted. Bare root in Zone 5 and colder can be a crap shoot for the fall just depends on the onset of cold weather and the severity of such.
I'm in Zone 5A (4/5 line), West Side, middle of the state, right on the lake. If trees don't have a chance to establish roots before going dormant here they don't have a shot the next spring. Unless its a crazy mild winter, why chance it?
I'm in Zone 5A (4/5 line), West Side, middle of the state, right on the lake. If trees don't have a chance to establish roots before going dormant here they don't have a shot the next spring. Unless its a crazy mild winter, why chance it?