This is a very interesting thorn tree. I've gotten several names for it so I'm not sure what it is yet. It is a native or adapted desert plant as I have seen several growing wild throughout the area. It makes a wonderful xeriscaping plant so I'll make it a point to find out what it is. It actually does better when the desert is totally parched. More on this below...
There was no question to leaving this tree in the plan. It's a great opportunity when you can plan a landscaping project to be able to incorporate existing plants into your landscape design and make them work well with the design. It's also a shame to remove a large tree or shrub that can give character, shade, and other elements to the design.
We had plenty of room in this design to keep necessary walking areas away from this bush. It should be a consideration when planning walkways and paths of how close they should be to plants and flower beds and what type of plants to plant. You should know how large plants will get as not to plant plants that will interfere with the walkways.