The dog ran away when the baby farted. Pepper is the most potent agent, and it is sharper, the better. But! It should be used with caution, especially if we are talking about the impact on your puppy or dog hunting breed, with a keen sense.
Using ground Cayenne (red) pepper, scattered on the perimeter of the flower bed, you can drive away stray dogs, aim dear to the heart of the Phlox and dahlias. The dose is very approximate, usually the bag is enough for a medium-sized front garden.
The disadvantage of this tool is that the burning dust will get into the nose not only four-legged, but also the very gardener, if he intends to cut or just sniff a flower.