My perennial guide lists helenium as a "water hog" so sounds like your plant can't keep up with the heat. We're expecting 30's for next week here so we can expect some issues as well.

Helenium is a wetland native....I doubt you have the humidity it expects when pushed with heat. It should recover every night if you provide adequate root moisture.

It might wilt less once its root system matures. In the meantime, can you put a bunch of mulch over its roots, and water it deeply or even use a soaker hose underneath the mulch?

When I used to grow morning glories against a south wall they did the same thing. Repeated wilting is supposed to cause a hormonal signal to slow the plant's growth, but those morning glories didn't slow down. They got through a screen and into my bedroom!

Helenium is another plant that I've tried to grow unsuccessfully, but that was years ago and I don't know whether there have been improvements that have made them hardier.

Sometimes there's more to it than a plant simply needing water and you run the risk of rotting the roots.

Thanks, everyone. I probably will give it one season and see. If it really is a thirsty plant, I probably will move it somewhere else next season..... I just wished that I had read about this before I bought it! Yikes... anyway, thanks again!