If you plant landscaped areas densely, dogs will generally stay out. Still, most dog owners recommend additional precautions: Plant in raised beds or on mounds, and start with 1-gallon or larger plants. Put up temporary fencing around newly landscaped areas; when you remove it, add a rock border or low fencing as a reminder to stay out.
Plant romp-proof shrubs and perennials like ornamental grasses around the edge of the garden. Put brittle plants like salvias in the center, where they'll be protected.