Rhus lancea (evergreen) - African Sumac, is very tolerant of most desert conditions except severe cold. Can be damaged at 20 F. Moderate growth to about 20 x 20 feet. Will drop some leaves during hot summers, so not a good choice near a pool.
Robinia ambigua (deciduous) - The Purple Robe Locust tree is a moderating growing shade tree to 35 x 30 or more. The beautiful flowers emerge in spring and typically last through early summer.
Sophora japonica (deciduous) _ The Japanese Pagoda Tree is a medium sized tree with fruiting pods. Moderate growth to 25 x 25 or more. Prefers good draining soil.
Sophora secundiflora (evergreen) - Texas Mountain Laurel. Is extremely hardy in the heat as well as cold. Slow growing (to 15 feet or so) with beautiful flowers. Give this one time to grow.