Very interesting series of replies. I came to this site looking to see if I was the only one that lost 95% (no joke) of her hostas.... We had the same warm/cold flip in weather here in the Hudson valley, and the ONLY hostas that are coming up for me (with only 2 exceptions) are seedlings from the original plants.
Probably lost 30 years of hostas, at least 8 different types, and dozens and dozens of plants. Entire areas of the garden are empty.
Besides irises, hostas are my favorite plants, despite fighting off the deer to keep them! The weird weather seems to have helped my ferns and irises, but the hostas are gone -- not even the rotting crowns mentioned above. It's like they were never there....
Will have to find a local gardening group to see if I can swap some irises for hostas....