It's hot out, but you don't need to read this to realize that. In oppressive and often dry heat, north Texas plants conserve energy by growing slowly, if they grow at all. Some may even go dormant and turn brown (but they're not dead).
The tendency is to water the vegetation a lot. But enthusiastic watering won't change the temperature one bit - and that's what plants are reacting to. Actually, too much water may even cause the death of a dormant plant, via root rot.