Help! My dog's a DIGGER

We have a farm where we allow our outside dogs to run freely. we got Jasmine, a German Shepherd, when she was 5 months old, had her spayed. She is now 1 1/2 years old. very smart. The other dogs never dug in my flowers. Jasmine constantly digs in my daylilies. She still chews on the plastic pots if I put one down or anything for that matter. I put big rocks on the dirt where she can't dig there again, but my gosh, I don't like rocks that well. Any advice from anyone would be appreciated. I really love her and will not get rid of her. Surely there's a way. Thanks.