Every year, come springtime, we rake up our old mulch and replace it with new. ( please note that I used We very generously, as I raked nothing!) Every year, once the new mulch is down, the dogs act like we filled the backyard with milk bones and try to eat all of the mulch. This year, to try and discourage the full out mulch feast, I sprinkled some cayenne pepper on the mulch.
This year, we also used something called Hollytone around the base of the bushes. Lucy has carefully stepped over the cayenne peppered mulch, and instead has eaten all the Hollytone! I originally thought I had some rogue squirrel burying acorns, but someone with muddy paws has given themselves away! No worries, Lucy is fine so far, but apparently can't be left in the yard unattended until this stuff soaks in!
Does your dog routinely eat crazy things? My cat eats hair elastics, so I always have to hide them!