When I'm trying to talk anyone into becoming first time gardeners, I usually suggest growing some kitchen herbs.
Some of these herbs do rather well in the Texas heat. In the Garden 101 story, I grow all three of the featured: oregano, rosemary and basil. I also grow Mexican mint marigold and summer thyme. In thisbone-dry and scorching hot summer heat, all but the rosemary have to be watered several times each week.
There are about a dozen varieties of basil to grow, each kind has its' own flavor. Bees love basil if you allow it to flower. Pinch them back if you want to get more leaf production. I have found that you can shape oregano rather easily. I use an electric shrub trimmer to keep mine flat and ringed around a featured kaleidoscope abelia I'm growing.