Anyhow, I just got some bare root trees european plums, which were shipped on Tuesday, and there is ice on the roots, and the moist packing is frozen as hard as a rock. Nice looking trees, just got very cold in their box on the way here.

I called the supplier and they said to keep them in a cool place, keep the roots moist, and plant as soon as I can (probably Sunday or so), and everything should be OK.

Just wanted to check here if this is accurate, or if these trees are goners,

Final answer will come next spring but I'd look at the roots. If dead you can probably tell now just like you would the top. If it's brown at the cambium layer they're likely dead. If healthy looking they are likely OK. Start checking at root tips and work back. Tips will be dead first.

Fall is for planting! I planted a few trees this time of year. I don't think it is an advantage, but they all did fine. This time of year the ground is a lot warmer than it will be in the spring. but once in zone 5 it's iffy to plant in fall. Seems OK here in zone 6. Even last year after the terrible winter, the one tree I planted in fall lived. Some older already in ground died though! I lost one tree this spring, bare root arrived in spring, didn't make it. So my fall plantings did better this year. I do prefer to order in the spring, but at times it's nice to have it up and running come spring.
Not just trees, bulbs, garlic has to be planted now, well if you want large garlic bulbs, you should plant in the fall in my zone. I put about 25 cloves in the ground 2 weeks ago.
You can plant in the spring, but they mature later and are smaller.

Burr is right! I am not sure how the ground will be next week when it's supposed to warm up to 40-something. I would pot them and keep them in the garage this winter.

I haven't had good luck with fall planting, but then again, I've only planted marginal trees in the fall. I'm concerned about my trees outside. We had such a beautiful fall. I picked my last squash two weeks ago! Now this...Ugh! Most of my trees still have leaves. My strawberries were blooming on Monday before I covered them.

Fall planting up here is iffy, but so is spring planting. The reason I ordered these trees now is they are a variety that appears to be closed out, they aren't available next spring (which is when I originally ordered them for). Good news is I did place the order with Stark's, so if they don't live I can get a refund.

Funny thing is, up until this week, it was perfect weather for fall planting. Mild days and cool but not frigid nights. Fortunately I dug the holes last week, so by Monday should be able to plant these guys.

When the cold comes, our min forecast is still about low 20F's. Even that some folks are concerned.

Well hope all trees make it. But you are taking unwanted risks....

Bare root trees do fine here. It's more common to plant them in the spring, but fall planting does work too most of the time. You just have to worry about what is going on now, an early cold snap that freezes the trees in transit, or makes planting them delayed.

There are quite a few trees that do quite well in this climate/zone (many apples and pears, cherries and a few plums). I have 30 or so of them planted, all from bare root, and most are doing well. Of course it is too short a season for some varieties, and I have lost a few trees too, but so do folks in warmer zones.

You may be surprised as to what sorts of fruit one can grow in the colder climates.

The absolute cold temperatures;
Days temp below -10F;
Days temp below -15F;
Days temp below -20F; etc
Temp extremes in November, April and probably May.

If you have such a large temp swings during shoulder months, then your effective hardy zone should be colder than the published zone.

The spring temperature swings can certainly cause a lot of damages.

The lowest we've gotten is about 26F at night.

This is why New Jersey calls itself the "Garden State"

We have one more cold night then back into the 40's during the day and 20's at night. A few weeks of that and these trees should do fine.

One year when we got to zero in mid-Nov, established trees died at an alarming rate- trees that are fine at -20 or lower.

If the trees were dug up in an area with similar weather I wouldn't be so concerned, but hardening off is a gradual process that isn't complete until January in most weather.

At least protect the roots with a thick layer of airy mulch and make sure the soil is wet enough to store heat.

Not that I have any experience planting trees in your type of climate.

The other way is to put the bare root trees in containers and store in garage. But this may not be practical if you have so many trees.

Good luck with your planting. Have you planted bare root trees in the fall in the past?

I agree with Hman that these trees are probably not as hardened off as would be ideal. But given the circumstances it's what I'll have to go with. Probably would not have done it except that the seller guarantees they will live. Although since they were dormant and in storage prior to shipping, they were probably in better shape than trees still in leaf when the cold snap hits.

I'm a huge endorser of fall planting, it is just the suddeness of the weather change that concerns me. The frozen roots are likely fine for the reasons already expressed here although, off the top of my head, I don't know what the roots can take. I've had bare root peaches in my truck that survived 20 degrees fine.