I think said something last year about this, but totally forgot about it til today. Squirrels will not dig in a pot that has been top dressed by that lousy evergreen top soil you buy at lowes. I was reminded today about that when I was checking on some roses I had transplanted into pots and other plants that were out. Every last pot not topped off by the evergreen was dug in and the two that were are untouched! Glad I noticed that again .. I'm gonna need to write that one down!