Crepe Myrtles! They love sun & once established, can handle drought like nobody's business. They make lovely small trees. You can get cultivars that only grow to 10 or 15 or 20' depending on what you want/need. You get gorgeous blooms & they will make shade for your yard & garden. The nice thing too is that they don't take up a whole lot of space.
Have a look. Crepe Myrtles for Texas!
http://aggie-horticulture.tamu...