How to keep a small blueberry plant in the winter.
How to Keep a Small Blueberry Plant in the Winter
Certified GKH Gardening Expert
Blueberries are naturally hardy, but the roots may still require some protection during winter by wrapping the container in blankets, bubble wrap, or quilt batting. Alternatively, you could sink the container in the ground over winter by digging a large enough hole to accommodate the container (up to its rim or a couple inches). As long as the roots are protected, they should live through the winter just fine.
If you decide to plant them in the ground, their care may be variable, depending on the type you have but mulch is good for additional winter protection. Here is an article that you may find helpful: https://www.gardeningknowhow.com/edible/fruits/blueberries/growing-blueberry.htm