My tiger lilies are large and beautiful. I have never divided them, and know that I need to do that. I live in Tulsa, OK, zone 7A I don't think the lilies begin to die back until quite late in the fall. Is there anyone else in my zone who grows them? Could you tell me when to dig them up, and is there a rubric as to how far apart they should be planted.

Thank,

Sammy