Planting time query

Does anyone have an opinion on how late can iris be planted in zone 6a?

Is late August too late for them to grow enough roots to survive the winter? Or do I need to control my iris impulses? (The answer to that is, yes, but still . . . .)

I think you can plant in 6a thru the end of August with no problems. I am in 6 ( sometimes I think its more like 5 as I am on a high hill). I have planted thru Sept and they are fine. I have planted in October and some are OK but they don't grow as well.
Thank God that there is a planting cutoff or I would be over-inundated with iris too.
Laetitia

As long as they have the approx 6 weeks to estimate roots. Here in zone 7 I plant until the end of Sept.

D

I think you might want to mulch with spruce branches or something similar if you are planting late. Make sure they are kept watered because they have to grow roots now.

Thanks very much!

That's interesting. The irises I ordered won't even be shipped until mid-September. But first freeze on average is on September 20. They will have no time to get situated before the freeze hits.

Or am I misunderstanding? I've heard that iris should be planted between September and November. Are they supposed to be planted after frost begins then?

I don't think so. I think they need to have time to put out roots, as people said above, like six weeks before the first frost.

I have heard recommendations that you mulch the first winter in cold climates if you are planting late. I think spruce boughs or something like that would help a lot without matting over. Why don't you contact your grower for info?