I wouldn't want to take any chances, explaining the wife that you killed the dog is... difficult? Having said that, I grow hops and have dogs. My dogs like tall grass and never seemed to have interest in bines. I was worried about the cones so I placed a bowl of fresh hops on the floor while watching a movie "not" paying attention to the dog, so they do their thing. No interest. Like Sirsloop said, a fence of some kind couldn't hurt. If you have an open yard, deer and other outdoor animals may eat more of your hops than your dogs. So I fence can't hurt. Just material to consider...