The diagram is nice, but pictures would be much better, as well as more information.
Do you have an irrigation system? Did you water properly? What killed you previous attempts? Did you mulch and fertilize? Do you have animals that ate your previous plants? Do you know what is in your soil (clay, sand, ph levels)? Shady area, hot and sunny?
You might also want to get a liscenced landscaper involved also. This might be a small job, but it sounds like you have already spent a lot of money and time killing previous plants.