Are they in too much sun? Did you water them enough?
I usually place a shade in front of freshly planted plants and keep them watered frequently.
Perhaps the black mud is not draining well. Hostas love good drainage, and like to keep the roots way down wet, but the crown dry.
Bernd

If you have a picture of the situation, showing the size of your transplants, it could help. You say it is shady, so sun exposure might not be the problem. More than likely the "mud" is just that, too muddy and not enough oxygen for the roots, so they are steaming and cooking. But seeing is better than guessing.

Like the blind man guessing about the elephant when he only touches the wimpy tail, it's hard to tell what we have here. :)

they will make it.. if you provide water ..

they just aint gunna be pretty for the rest of the year ....

some guy did a brilliant post on HOW TO TRANSPLANT A FULLY LEAFED OUT HOSTA ... or some such nonsense...

perhaps if you use the GW search up above.. with that title you will find it... in case you do it again .. but also ... to compare your process to his ...

his brilliance revolves around using tape.. has he ever mentioned such.. lol ...

anyway.. they will be there next spring.. trust me ...

ken

ps: you could have left them on the driveway.. and they would still be there next spring ... if you figure out a way to kill them.. let me know ....

Very little sun, and tons of water! Draining though might be a good place to start. It was nice and dried out to dirt when we added the pond mud/dirt to it.