I just paid a landscaper to dump 3 inches of mulch over 5 inches of topsoil
over a bed of existing hard clay soil in the front of our house with the
intention of softening the digging area for planting shrubs this fall.

Other projects have taken priority and I may not get to this as soon as I
thought, therefore I'm seeking non-biased opinions on this:

* What is the latest I can transplant shrubs from the nursery into my front
yard in New Jersey, USA? (Abbreviates, etc.)
* Will this topsoil harden and make it more difficult to dig if I do not
plant until next spring?
* Why is it better to plant in the fall, or is this a fallacy?