I was just looking at an article at the vet's "Making Your Yard Safe for Dogs." I didn't read it because we don't have a dog right now. I think it was in National Wildlife, a recent issue.

http://www.nwf.org/nationalwildlife/

I never heard that a dogwood is bad for dogs. I can't imagine what part of the tree would attract the dogs anyway. We have two dogs now and I have had dogs all my life and dogwood trees everywhere I have ever lived with absolutely no problems, so I say go for it! They are beautiful and the only worry is that the squirrels will get so fat from eating the berries, they won't be able to outrun the pups!