Hostas

Either spring or fall is a good time. I like to divide in the fall just as the leaves are starting to yellow. Like any fall project that involves root development be sure to keep them moist over the winter if it is dry.

Dennis - Johnson County Extension

I've divided hostas in the spring and in the fall, and they do well regardless. They are very tough and adaptable plants. One year, I dug out some hostas and put in a wheelbarrow, and forgot about them for a few weeks. They sat outisde getting rained on, drying out, baking in the sun. When I finally got around to planting them, they did great. I wouldn't recommend you abuse yours the way I did mine, but that does illustrate how resilient they can be.