The local extension agent has suggested that I split up my irises so that they will grow flowers. They have not been split up since they were transplanted in April or May of 2008 and except for 2009 have produced flowers every year until this year. So I'd like to know, when is a good time to split them up and transplant them. Is it too hot to do it now? I am in central OK. I'll also be getting a soil analysis to see if that is a problem.