If your pet is eating plants, it could be a sign of a nutrient imbalance, so schedule a visit to the vet. Most likely, though, this mischievous behavior is a sign of boredom. Redirect your dog to another activity, like a game of fetch, says Kirsten Theisen, director of pet-care issues at the Humane Society of the United States. And make the garden a less desirable spot to dig in by placing flat rocks around plants and spraying the area with a mix of water and lemon juice (most dogs dislike citrus scents).
Martha Stewart Living, May 2014