[Corin Stormhands]

Okay, OT got your answer. But, can I add a little smidgeon?

I need all the help I can get! I was asking because I'd just as soon not divide them if I don't have to.

[Wneighbor]

Rule of thumb around my garden. If its a bulb or a rhizome start THINKING about digging and dividing every 3 years. Uh. Some of my things get divided less. If one year they suddenly aren't as thick as they were last year (and you see no severe weather reason for this) then that year you need to thin. Do that thinning in the fall/winter. Here in Texas I usually shoot for October or February for this. I don't know about ya'lls seasonal things. OT will know more about your area for that.