We have this problem with one of our dogs as well. The vet said it was best not to add anything to her diet to change the pH of her urine. What we have found is that the "immergrun" in parts of our garden is not affected by her urine. The latin name for Immergrun is "vinca minor". There are several varieties and colours. It stays green all winter and blooms in spring. It requires very little work to maintain.

If you are going to put down rocks or stones in a special place for your dog, do consider adding additional drainage, otherwise unlike grass, the smell of urine will remain. You will want to hose down the stones.

Unless covered in snow, our dog will tend to go to her favourite spot in the garden. Even our other two dogs have their favourite areas in the garden.

We have also have to put down new seed this Spring as we dug out ivy, which was an absolute disaster for the dogs. They get all tangled in it not to mention what it does to the other trees. The immergrun doesn't have the same problems. Other options are "Waldsteinia".
I like this website for researching information about plants. (German only)
http://shop.garten.ch/cgi-bin/garten...&funktion=shop
They publish a book which is available at the garden centres for reference.

In my experience, many gardeners have little experience trying to accommodate dogs' needs into the garden. Many think dogs destroy the garden but in our experience, the dogs walking and running on the grass provides natural aeration throughout the year.