Hosta have a problem transpiring when it is hot and moist, I think any thing on the leave will make it worse.

I offer that hosta are not shade tolerant they are heat intolerant, when it is hot they need to breath.

That said, run the experiment with a double blind to see if it helps.

I don't think I would spray a growing plant with wilt-pruf....that's for evergreens that tend to wind burn...
But try ti and tell us!
Linda C

Firstly, do not spray any blues with Wilt-Prus. It will remove the glaucous coating and you will have green (or green spotted) hosta.

It is an anti-transpirant so theoretically it should work on the drying out part, but not on the sunburn part. I think the drying out is a result from burning and too much sun and Wilt-Pruf will do nothing to help the plant out under those conditions.

I would try it on something I don't care about an move my valued hostas into more shade.

Alexa

Thank you all. I will not spray them. This is there first year coming up from the ground. Someone told me the main problem was that when I put them in the ground last year they had been protected and grow in a greenhouse and where probably not acclimated to direct sun.

"I put them in the ground last year they had been protected and grow in a greenhouse and where probably not acclimated to direct sun."
Sam

That was last year, it is gone thank goodness!

Samsthumb, the person who told you that about being in the greenhouse and not being acclimated is probably right.

Even if they were grown in an open field, as some are in order to get maximum size quickly, they may have gotten shade-acclimated while being warehoused and then while being sold.

I've almost killed hosta entirely by putting them in sun or half sun when new, but they came back the next year nice and strong, and weren't as fussy.