If there's one plant that should be on everyone's list, it's Snow Princess, a unique breakthrough in the genus for heat tolerance and extended season performance. It is extremely vigorous, and because it puts no energy into setting seed it has an incredibly long bloom time. Creates a great hanging basket or window box and is a perfect filler in combinations.
Drought-tolerant plant and heat resistant, Alyssum is an ideal flowering plant for Texas. It does well in full sun or afternoon shade and is tolerant to cooler weather, as well. It is treated as an annual, but once it is established, it will reseed and come back year after year in almost any soil.
Sow in early spring, after the threat of heavy frost. It will bloom year-round in frost-free climates.