I've not done any thinning of my irises for about 10 years. I know the recommended timing is after they bloom but I don't want to go through another spring with with this ugly mess (I have 5 more clusters like the one in the picture). Anyway, could I thin/transplant now without killing them?
Thinning Iris Plants
Certified GKH Gardening Expert
Yes, after blooming is the recommended time, that said, if the Iris are indeed very overgrown and in need of attention, go ahead and divide the plants now.
They are probably not blooming as much now if they are overcrowded.
You can discard any damaged or diseased plants and replant the healthy rhizomes.
You may have less flowering or in some cases no flowers this spring, but Iris will make a quick recovery.
They will be back!