I'm nowhere near your climate, but I've never seen Husker Red (or any other penstemon) flop on the ground. None of the varieties I've ever grown have needed staking; far from it, they're all very upright growers for me that mound rather than sprawl.

You didn't describe where you planted the penstemon, but you might be on to something with the not-enough-light comment; mine are in full sun (I bet it's more than 8 hours every day). They get an average amount of water -- the beds are watered regularly by the irrigation system, but we aren't water-wasting crazy people.

After mine bloom, I typically let the black seed pods stay on the plant for awhile just for a vertical accent, and then eventually I cut the flower stalks. I don't cut back the foliage at all, so I can't speak to whether you'd have success. Mine stays a nice neat clump the rest of the season.

Sorry, I don't know if I was much help at all!

In the large collection of Penstemons at the Green Springs Garden Park in Alexandria, VA, I did see a couple varieties that were staked. There's a very xeric looking one, with perfoliated leaves and blazing red flowers, that seemed to be leggy in the wet summer climate. But most were not and didn't need it.
Note to penstemon collectors: one of my best performers in the mid-Atlantic is 'Lilac Frost' from Plant World Seed. Drought tolerant, wet soil tolerant, heat tolerant, blooms all summer into frost, fast to develop from seed and cuttings, a really amazing perennial that would win over anyone.

Here is a link that might be useful: http://www.plant-world-seeds.com/store/view_seed_item/1026?actionName=search_for_item&search_string=penstemon

FWIW, I don't have penst but put in a new bed last year where I dug out daffodils that flopped. The newly-planted artemesia and sage? fell over with the first rain and never recovered for the season, sulked, one climbing rose did well anyway. There is a large flowering tree that sucks out nutrients. Last fall, I spread a bag of compost over that bed and tucked it in generously with leaves (have to conserve my purchased mulch). A little flopping of one plant this spring, but all the others have recovered, are standing erect, and art is multiplying, only a little morning sun which could be a factor.

Now I started another bed with plenty of sun where I put some meadow sage. Fell right over. There is competition with another tree but not nearly so close. So I'll compost this fall and look for them to stand up straighter next year if they survive.

Apart from what the other poster said about one variety seemed to be needing staking, I'd see if you are nutrient deficient there, don't know if you amended you soil or not, but what I did may help yours next season, if it survives growing a season. I wouldn't give up on it. A little fert might help, but I don't know what would be good and you don't want to overdo that.

I've got pieces of bamboo stake, maybe I'll help my new sage along with that this year. If they flop next year, I will pull them out. Maybe some weaker new plants just do that when so young, transplant shock, and hard rains from the git go like we've had here.

From what I've read on some other gardening sites, Penstemon can indeed get floppy if it gets too tall, and will benefit from a hard pruning after flowering (this has the added benefit of encouraging rebloom).

Mine is only getting about 4 hours of direct sun per day, but I'm in the south, where most perennials can't actually tolerate 'full' sun.

Do they ever! I have Blackbird and it flopped all over the place. It was in full sun and rich soil and got to be at least 5 1/2' tall. I had it in a tomato cage and it still flopped. And it never stopped blooming, so I didn't cut it back for the longest time. It actually got to be rather annoying.

I cut it down to stumps and moved it this spring (just to show it who's in charge - the person with the pruners and the shovel ha ha!) and that set it back for a while, but I can see it is gathering strength and about to make another move. I have already caged it.

You have the wrong penstemon. What you want is penstemon tuis, often marketed as Gulf Coast Penstemon. It has a lovely pale lavender bloom, is evergreen, and the foliage has a red cast to it. It's absolutely foolproof in the hot muggy south, and seeds around just enough that you always have plants.

Donna, don't Gulf Coast Penstemon require a lot of moisture? My soil has a fair amount of sand, and dries out very quickly.

My main stalk broke on my beard tongue penstemon due to a storm. Should I cut it off the rest of the way? Or is there something else I can do?

Cut it back to 6” from tge ground this will encourage more flowers