How often do you divide? Even SDB's?
I planted TB's this August so I know I won't be dividing them yet, but I have SDB's that were planted last fall 2008. I don't know if they will need to be divided next August or not. How do you know when they need it? How often do you divide? Do I leave the fans on over winter and remove late winter/early spring 2010?
Thanks all, I am pretty new to this iris thing :)