Here is the situation: I have six inches between the cement wall and the septic drain field. I want a green screen between myself and the neighbors on the other side of the short cement wall. What can I grow that will give me a green screen and not invade the septic system pipes? All I can think of is some sort of climbing vine, but I am not familiar with which root systems could be a problem.
You have a real challenge with your situation. Most of the literature says that you should not plant any large shrub or tree within 30 feet of a septic system drain field.
Roots growing into the drain field is a serious concern. They recommend consulting an expert if you do want to plant near a drain field.
Instead, you might consider installing an attractive fence and/or using containers to grow plants in. For example, Camellias can be grown on a trellis from a container. They are evergreen, and will also flower.
Another vine-like plant is star jasmine, Trachelospermum jasminoides. It is evergreen with fragrant white flowers.