How do I protect blueberry trees and brushes in the winter?

Answer 1

Just give them some fresh mulch.
They're really hardy .

If you have a problem with deer, you'll have to put a fence around the bushes.
http://fivewells.blogspot.com/2006/03/blueberries.html

Answer 2

Depending on your zone, you may want to wrap them in burlap (probably not necessary though unless you are in northern Canada or something). The other answerer has a good point about deer, rabbits, etc.- if they eat the bark off of your blueberry plants it could really harm them. Wrap chicken wire around the plants to protect from predators.