I planted a fruitless olive in a similar site. It's slow growing (except the darn suckers that pop up and need constant snipping off). It is low litter and has a nice canopy. Avoid desert willow......what a mess that tree makes.

Thank you Mary, that looks like a good candidate! I like the way the trunks can get twisted and unique looking. Also seem to be about the right size and shape. How slow growing? If I planted a 6' tree, how much could I expect it to grow per year?

I planted mine around 2010 in a 24" (or is it 27"?) box and it's now about 20' probably.

Another one to look at is the Vitex or Chaste Tree. I have two of these, they are somewhat low litter, they drop a blanket of small vitex seeds. The spring/summer flower display is impressive, also can get a multi-trunk one. Don't know if it fits your roots requirement, mine are planted away from fences, driveways, etc.

We used to have a poster here, AZTreeLvr and she always had lots of good info. She moved away and this board has been so quiet she rarely posts. Maybe she will pop by.