I wish someone closer to your zone would respond, I can plant here through winter if the ground is not to wet to spade. I'm not sure where the regular colder zone posters are, but hopefully someone will show up here soon....

It looks to me like gardeners in Z5 are still planting on the Perennial Forum and they don't seem concerned about the date. I think I would have liked to see you get them in the ground 2 weeks ago when they arrived, and Yes, you need to loosen up that root ball well when planting.

I'm a little concerned you will be leaving and won't be there to make sure they have water if you have cold dry weather before snow cover or frozen ground. A good layer of mulch over the root zone will help to conserve moisture and may also help prevent frost heave.

60's daytime and 40's nights isn't cold, its good planting weather. I just don't feel confident in knowing what the next 4 - 6 weeks might bring in your zone to tell you to definitely plant.

All in all, they'd be better off in the ground than remaining in their pots. I completely agree with morz8 about mulching and watering. I think I'd also put up a burlap or other form of screen even though this is a deciduous species. Anything that helps to keep temperatures stable by blocking intense direct sun and protecting the bark from winter wind dessication will help.

Thanks to you both for your replies. I'll get them in the ground tomorrow and mulch well. I have stakes and burlap and leaves. Thanks for the suggestion.

ML