I have frozen a lot of different foods, but had not tried freezing mushrooms. I wanted to be able to take out just what I needed when adding to a recipe.
So I tried the same method I used for blueberries.
Once they were frozen I placed them in a zip-lock bag.
They worked out great. They still retained their flavor and texture.
I froze them for at least a month and they did great. I do not know how long you can actually freeze them for. Would have to experiment with different times.
You could look it up in the Ball Canning book. I do not own an up to date book at the moment.
I will continue to use this method from now on.