Experts and BHG readers answer.
Dog Urine Killing Boxwoods
Thanks for writing. Your best solution would be to train your dogs, which as it sounds like you've discovered, can be difficult. But it really is the best solution in the long term. (There are motion-activated sprinklers marketed under brand names such as Scare-Crow which can be very effective in changing a pet's behavior.)
The problem on your boxwoods is the amount of salt your dogs' urine. If you're able to spray your boxwoods off with water each time this happens, it will prevent the damage. Also: Be sure your boxwoods are well watered. It's possible the damage is happening because there's salt buildup in the soil (and not on the leaves) --- so keeping the plants very well watered should help dilute the salts in the ground.
Good luck. I hope this helps!
Senior Garden Editor, BHG.com"