This year my penstemons are doing the same thing. They're growing low. They're usually the height of hollyhocks by now. Growing conditions this year, likely due to the temps, are probably the cause.

Well, if you keep watering them, they will probably survive and bloom next year. If you stop watering them, they are guaranteed to die and set you back a full year.

I'd keep watering them, changing from frequent to less frequent and increasing the time as I decrease the frequency. You want to water them deeply to encourage the roots to go deep where they will be safe from the June winds.

Mulch that area to conserve water.

Thank you both for the encouragement and advice. I will definitely continue watering as prescribed so long as I know there's a fair chance for some of them to survive.