I apologize for this delayed reply to your gardening question and hope it is still helpful to you.
There are a number of different species and varieties of Penstemons. Some would be very well adapted to your area while others would not. However I don't think of them as a good groundcover plant. They are more utilized as a perennial flower border plant. The following website lists some great ground covers for Alabama gardens:
Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!
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