Question
I recently moved into a house (in central South Carolina) and there is no shade in our back yard.  The previous owners installed a French drain which runs about a foot away from our back privacy fence.  Our house sits in the valley of a two small hills so all cars and neighbors can see into our back yard as well.  I want to plant some shade trees that would also provide privacy along the back and side fence, but I am worried about the roots growing into the drain line.  Can you suggest some trees that would provide shade and privacy but not interfere with the drain?  The backyard is exposed to full sun and the soil holds moisture fairly well.

Answer
Your Ag Extension has provided excellent resourses for So. Carolina. Here is a link to their Tree Guide - pay attention to the "Remarks" column (i.e. Ash have "large surface roots", so avoid this species for your planting locaton):

http://www.state.sc.us/forest/urbsg04.htm

If you want to see pictures/illustrations of a particular tree,or if you want to know what it looks like:
http://www.clemson.edu/extfor/youth_education/bul117.htm

I heistate to select one for you, as I don't know how big a back yard you have, what size you are looking for, if you prefer evergreen por deciduous trees, the depth & size of French drain, or how far away you intend to plant the tree from it (I'd suggest a minimum of no closer than 5 feet away).  I would suggest an evergreen, because their roots generally tend to be less invasive, and will give you year-round screening from the neighbors.

Also, as the tree grows, it will heave the area around it up, changing the drainage pattern and may effect the flow within the pipes of the drain...

Best of luck!  ~Marc