What do I do about a dog that is intent on excavating our yard, digging hole after hole?
Many terriers and some Nordic breeds are genetically predisposed to digging. It's best to supervise your dog outside as a puppy. If the dog has never developed the habit as a youngster, odds are that it will never start.
Unfortunately, this doesn't help dogs that are already members of construction unions.
First, fill in the holes and place some of your dog's own feces in the hole. If the dog digs that place up again, it may, in essence, say "yuck" when it encounters that nasty surprise.
Reprimanding Fido probably won't help, even if you catch the dog in the act. Despite your frustration over your rose bushes, absolutely don't physically punish the dog. After all, it's smart enough to understand that it shouldn't dig when you're supervising, so you don't want to further encourage it to mine like crazy when you're away.
So, you've got to be smarter. Secretly catch your dog in the act. Hide inside or behind a tree or a fence. As the digging begins, toss an empty soda can or two, each filled with five or six pennies, toward your dog. The idea is for the dog to be startled by these terrifying pennies from heaven. Some really persistent dogs won't care -- and will continue their re-engineering. Again, hide out of sight and turn on the water hose, full blast, or blast away with one of those power water guns, when you catch the dog in the act. It's imperative that the dog not understand that you're the one delivering the punishment.
Some dogs will enjoy nosing around basketball-size boomer balls, (available at most pet stores), enough to keep their minds off digging. Make other toys available outdoors as well. A great alternative -- albeit not always practical -- is to offer the pooch somewhere it can dig. Construct a canine sandbox. Remember, a bored dog is a dog that will get into mischief.