Cold Frame? Not So. I lived in Colorado Springs one winter (that was enough for me) Here I pot them up (all types of irises) in a mix of topsoil, compost, sand. Put the pots in a bed I made specially for them and let nature take its course. Why?
The strongest seedlings germinate, the strongest seedlings survive, and I don't have time to water them through the winter and spring.
I get 60-80% germination except with Arils and Aril breds which are lower but strung across years.
ok, so..I already talked to my hubby about cutting a bunch of PVC pipe for the seeds, and I plan to put them in a 'frame' of some sort, and then put them in a special spot in the back yard.. a place that is not condusive to snow drifts and gets a decent amount of sun. Will the seeds be ok if it freezes and thaws a few times?
The bees were very busy this yr. A species X plant (aphylla x picata TB seedling) had pods all over. They have been splitting while I was doing other jobs. Some seeds ended up on the ground, but those have been retrieved. So I have 2 small apron pockets of pods & seeds to sort. I had put my gloves in the other pocket. Most of the seeds will be sent to the British Iris Society which sells out of pogon seeds.
I got two to germinate, but they died while we went on our June camping trip.. &:-( Oh well it was just practice anyways... I didn't try to cross any at all this year, but got a surprise bloom from who knows where! I seem to remember a seed pod a few years back.... back before I was really paying attention... it's the only resonable explanation for this bloom that I never saw before. This bloom came out of one of several rhizomes that I thought were all National Velvet.
National Velvet has been growing next to Tuxedo for a few years in my back yard, so I nicknamed this 'Velvet Tuxedo'. I think I'll just keep it as my 'pet' iris.. &:-)