We have had unseasonable hot weather for approx 2 weeks with no rainfall, I notice some of my semps have curled up. I'm guessing this is from the hot weather and no rain. They get sun from early morn until approx noon.
As Yogi Berra said, “It's tough to make predictions, especially about the future.”
They curl in if there is a lot of heat. They can even grow less long leaves due to that.
When there is a lot of overcast skies they will open up, when there is too little light they will curl down generally and lose color.
But even harsh sun can remove some of the interesting colors of a particular cultivar.
Rj, good to hear they are doing better. I had the same problem with things drying out this spring. I have never had to start watering until July. This year I started watering in May.