Jeanne will probably chime in here since she lives in Texas. Recommendations from me would be the viticellas which tend to stand up much better in my zone 7a heat and humididty than any of the type 2 large flowering hybrids. You could also try a few of the native clematis such as texensis which is native to your state.

Miguel is correct..The Viticellas/pruning group 3's adore our climate..but they also need to be watered..so plan on planting them where you can get to them to keep the soil moist..mulching also helps..Jeanne