I moved hosta in the middle of summer last year, and most took off in their new location right away. I did lose a few, but not many.
Hosta are pretty tough - before I could afford to spend extra money on plants, I used to check out the end of season plants at the big box stores. I would buy a pot or two of wilted hosta for a buck, then come home and split them so I could spread them out along a shady west wall of my garage. They took off, even when I had to replant them after the dogs dug them up.
I have a friend that had to dig up her gardens a couple of weeks ago for a remodeling project. All of her daylilies and iris are in plastic bags in a corner of her garage and will be there for another month yet. I think as long as they are kept out of direct sunlight, however you store them will probably be OK for the majority. ~Jan
