Answer: Blueberries thrive in zones 3-7, and the roots of most cultivars are hardy to -40F. Yours should be fine over the winter if you just leave it out on the deck or patio. If you're really concerned about it being exposed, move the container next to the foundation of the house where it will be somewhat protected from the elements. Blueberries produce better if you have two cultivars, so you may want to get another bush to encourage lots of fruit. Blueberries like a slightly acidic soil, so feed with an acidified fertilizer in the spring, or mulch with peatmoss. The plants prefer full sunshine and well-drained soil, but don't mind wet feet during the winter months.
It sounds to me as though the top of your plant died back and the roots are sending out new shoots. This indicates it was stressed for water or it was in a spot that got too hot. You might try finding a garden spot with some protection from hot afternoon sunshine during the summer months. Filtered sun or even full shade from noon on should make it happy.
Best wishes with your garden!
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