Aspen is good and carefresh is good. Another thing to consider is that if she has plenty of hides in her enclosure, she won't burrow as much. You don't want to take away her ability to burrow though...I know it's frustrating when they hide all the time, but that is a natural instinct with garters...it makes them feel safe. I have noticed though, and have heard other members say this as well, that once I put lots of hides in my enclosures, my snakes stopped burrowing so much...they do still hide though...it's just something they do...but she will do it less as she gets used to you.