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Although native plants are mostly carefree they do need watering the first year during dry weather. Fall or spring planting is OK. It is vital to water the plants when rain is scant right up until the ground freezes if you plant this fall. It doesn't need much water after leaf drop. Dry winter winds strip moisture from the vines. If it goes into winter already dehydrated, it is more likely to suffer winter kill and winter dieback. Virginia creeper grows and spreads in every direction. How will you handle vines that creep outward instead of upward? It should not be allowed to climb trees. While it isn't as bad for a tree as grapevine, it can adversely affect branches by smothering the leaves and inhibiting tree photosynthesis.
https://www.gardeningknowhow.com/ornamental/vines/virginia-creeper/virginia-creeper-maintenance.htm

Your neighbor is within his rights to prune anything that comes over the property border. Some states have laws about pruning if it is going to jeopardize a tree's existence. Your Virginia creeper will come back; I have no doubts about that. Can you give it something to climb on your side of the property like a tree or chain link fence.? A trellis is no match for Virginia creeper unless you prune regularly but a pergola would work. Keep it pruned so it doesn't wander back to your neighbor's property; it is a simple task and preserves good relationships. Perhaps it is time to relocate the creeper?

There is quite a lot of conflicting evidence of, exactly, where these plants can survive that far North. Although fit is found in Canada, it seems to be only native to the Eastern side.

It could be that you are in an area that is slightly too cold for this plant, as this is what triggers the color change (senescence) and falling off (abscission).

Alternatively, if you find that it does well near your area, elsewhere, then it may be a case of lacking phosphorus in the soil.

This article will give you more information on these plants: https://www.gardeningknowhow.com/ornamental/vines/virginia-creeper/virginia-creeper-maintenance.htm

It will root in a potting medium but you can always try water, too. Here is information on taking cuttings and also general care of Virginia Creeper.

https://content.ces.ncsu.edu/plant-propagation-by-stem-cuttings-instructions-for-the-home-gardener

https://www.gardeningknowhow.com/ornamental/vines/virginia-creeper/virginia-creeper-maintenance.htm

It sounds like a good application for planting Creeping Virginia.

https://www.gardeningknowhow.com/ornamental/vines/virginia-creeper/virginia-creeper-maintenance.htm