In Z5a waiting until next spring is the best course of action, imho, especially since you have put so much time and care into these plants. Deep cold with little or no snow cover is just too likely to cause serious damage for the very reason you cited: too little root mass. Fall planting in general is not a good idea for Z5 (and parts of Z6). All of the dangers are greater for evergreen plants like boxwood.

i dont do boxwood ... so i cant be specific ...

but if i had 60 ... i would probably do half in fall .. and half in spring ...

mostly so life next spring.. doesnt get in the way again ...

how big are these things ... how big a gob of soil can you take with them ...

root pruning the prior year.. is real old school.. the thought now is.. not to stress them one year.. and then move them the next year ... increasing stresses all around ... but that is water under the bridge ...

does you project.. require all 60 ... if not.. experiment ...

you better hope the politicians are right.. on changing your zone... i have no faith .. as i had two z4 winters in a row.. in my z5 MI .. just north of toledo ...

ken

Ken- I know there is a heart of gold under that rough exterior, lol. I just recently started up on gardenweb after a few years of absence, but I remember you fondly. Always good advice, if not blunt. I guess I am an old school kinda gal. If it's worked for me in the past I will continue to do it. The plants are 2ft tall and 1 1/2ft wide, with the root ball the same width and about 1ft deep....so a good "gob" of soil with each. They've been there 5 years. The project requires 50 shrubs, so 10 for insurance. I think it would work transplanting them now if I kept them moist and mulched, it's already getting cooler here. It's the winter dryness/winds I am concerned about. Maybe a burlap screen for the first year or two? Thanks for replying.