Hi Rebbeca and welcome.
Z3, cold winters, do they come early as well?
Okay, here in the Great Lakes we are having a record cool summer and that makes a difference with planting/transplanting.
If you want to transplant the Sand Cherry bush, here is what I would do.
Keep an eye on your weather report. If you are going to have a couple of cool or cloudy days (rain is a bonus) get read to move.
Hydrate the plant well the day before and the day of the move.
Have your new hole dug and possible get some 'Root Boost' Schultz and Miracle Grow have this product as I'm sure other do as well. Follow instructions.
Do this in the evening or cool of the day.
Recent research (MSU) shows "NOT to prune back" if possible. While foliage can strain a plant, it is also needed to feed the plant as well.
Keep well watered, (not standing in water)
The sooner you get transplants in the ground, the sooner they can establish new roots to help survive a cold and harsh winter.
Even after a shrub/tree drops leaves, the roots continue to grow until the ground freezes (get them established soon). Water until ground is frozen.
Mulch this fall to help insulate and frost upheaval if that is an issue where you live.
You can prune back as needed the following spring.
Ron
www.gardening-for-wildlife.com