Interesting. I've got 2 new Carpathian walnuts, which are an English walnut type. The smaller tree is free standing. The 10 ft tall tree just came out of a pot, so it is staked, but loosely. Enough support to steady the tree if the wind shoves on it, but the wires are loose enough so they aren't providing any support when the air is calm and the tree isn't moving. The tall tree is self supporting, but it did have the wind blow it nearly over when it was still in the pot. The top of the tree is large compared to the root ball and I was worried that if we got one of our 40 mph winds, it would shove the tree over and rip the root ball out of the soil. Both my walnut trees have sturdy, self-supporting trunks. It's hard for me to imagine a walnut simply flopping over. Maybe a very young small tree would droop over if it needed water? Trees need "exercise" and perhaps a small tree that had been too sheltered might be weak. The wind blowing the tree strengthens the trunk with the movement. If a young plant has never been exposed to any wind, it might be weak, although my actual experience with weak plants has been limited to seedlings started inside the house. No problem any more with weak seedlings. Mine get their daily exercise from a small fan blowing across them.

If you're going to attempt J.regia in zone 4, you need to be certain to get 'Carpathian' strain trees. Not all 'English/Persian' walnuts are created equal, when it comes to cold-hardiness. That said, Grimo Nursery, one of the farthest-north nurseries I'm aware of selling nut trees says even in zone 5, they need winter protection. I have a friend in Flint, MI (5b) who grows a number of J.regia selections. Check out the list of 'experts' at the NNGA website (and look around the rest of the site, while you're there). They'll be glad to answer questions or make recommendations. Here is a link that might be useful: NNGA Persian walnut experts

While your local extension agent may not know anything about walnuts - there are folks whom they can call upon for information. Former county ag agent here only cared about tobacco production and not much else; current one will help with anything - and if he doesn't know about it firsthand, he'll hunt up the appropriate university 'expert'. While he's well-known as a pecan expert for his 45+ years of work with them in GA, Dr. Darrell Sparks(or some of his fellow researchers) may also have some recommendations for Carpathians suitable for GA - or they may be able to say, unequivocally - "Don't waste your time with them." Here's the section on Carpathians from an UGA Extension bulletin on minor nuts/fruits: Carpathian Walnut The Carpathian walnut (Juglan regia), also known as Persian or English walnut, is believed to have originated near the Caspian Sea in Iran. The Greeks and Romans brought it to the west, and it was eventually spread throughout the Far East and North America. Carpathian walnuts are sensitive to climate extremes and are marginally adapted to Georgia. They are quite susceptible to spring frost injury. Temperatures below 12 degrees F will kill some varieties, and temperatures above 100 degrees F will cause sunburn on limbs and shrivel kernels. The walnut is monoecious, but cross-pollination is required; so at least two varieties should be planted. Carpathian walnuts do best on deep, well-drained soils with a pH of 6.0 to 7.0. A spacing of 25 feet by 25 feet is ideal. Carpathian walnuts are propagated like pecans, but no specific variety recommendations can be made.

'N-1' is a seedling selection from Clifford Dabbs of Utah. It's several weeks ahead of the late-vegetators being sold today (vegetates later than current cultivars.) Here are a few photos of the trees from these nuts. These are 30+ years old (grafted.) Juglans regia 'Fately-5' or 'Fately #5' Juglans regia 'Broadview' - 1/3 of the tree broke off this year. Juglans regia 'N-1' or 'Dabbs N-1' - a selection of the late Clifford Dabbs of Utah. This cultivar vegetates much later than any of the current cultivars being sold. Not in commerce as of 2016. Selecting a pollinator is going to be a challenge. I don't know of a good pollinator for it. Crops are sparse. There are about (6) other Persian walnuts near this tree. All the above are close to each other with other nut trees separating them. Dax