My dogs keep peeing on my plants and killing them do those dog repellent pellets work? Any other suggestions?

There are products such as GreenUm that you can add to your dog's food that will make his urine plant safe. I've never had need for them, but I'm told they work very well! Most pet stores will have multiple products to choose from that will do the trick.My dogs keep peeing on my plants and killing them do those dog repellent pellets work? Any other suggestions?
As long at it dry in the area all you will need to do is sprinkle cayenne pepper on the ground around the plants.This does no harm to the dogs or the plants but it will keep the dogs away.I use this method to keep dogs and raccoons out of my garbage too.My dogs keep peeing on my plants and killing them do those dog repellent pellets work? Any other suggestions?
The only thing that really works is a fence between the plants and the dog.
electric fence. or a legit fence. or a leash. :)
Moth balls.