Oh, no. It can affect spring bloom. This happens in CA all of the time- the trees think it's spring in January, blossom out, then get frozen in Feb. I'll keep my fingers crossed for you, and maybe someone from your zone will chime in.
Renee

I'm just outside of Detroit, I wouldn't worry overmuch. It's still pretty cool for them to be doing anything other than growing some new leaves, they're gearing up, but they won't bloom until it's in the 50's for a while, it's not that warm yet.

We had a 50 degree day yesterday, after many freezing ones. They still look the same. I hope they will be ok!

me too! I'm gonna be really unhappy if they set buds and then freeze, i got an order from tennessee last summer (not this one just past, before that) and am really looking forward to seeing all of my new plants bloom, and if they don't....

Before this hard freeze coming , is there any point to my covering the small iris bed which has plenty of buds developing and some that have broken and ready to bloom?
I just moved to this house and it looks as though this bed of iris has been here for several years.

I was thinking I'd cut those buds closest to opening and cover the bed with a suspended quilt.
The bed is in full sun against a brick wall and they probably have no need for protection.
I'm just trying to protect the developing buds.

Will two nights in the 20's destroy these buds?

I have had this problem a lot where I live. The weather is always vacillating between very cold and above freezing all winter. What I think it does to iris blooms is it doesn't so much cause the blooms to die, but the stems are twisted and short, so the flowers are down inside the plant. I think it takes below 20 degrees F for this to happen, though, after a warm above 50 degree period. Good luck. I hope things turn out okay.