In article s3R0a.84$Lq.5243@stones, h.neil@whichREMOVE says...

Any time during the dormant season is fine although, for obvious reasons, it
is best not to plant them when the ground is frozen.

I notice the so-called dormant bare-root trees in Woolworths have
already started sprouting and wilting in their wrappers. It's hard to
know what the dormant season is these days. I'm getting all my stuff in
containers to be on the safe side.