Re: Tender growth vs cold......
Iris, I agree with the advice which Marte gave you. It is typical here for
our new plantings to still be in an active growth stage when heavy frost
arrives. I had never thought of it as unusual in fact.
Actually growth will continue after light frosts. Sorry I don't have a
specific temperature but it seems to me that it will take a temperature
under 28F before the irises will pack it in for the winter.
I think you should just relax and let things happen. We have had early
frost and very late first frosts and I have never noticed any effect on the
plants or the following spring blossom.
What we hate here are the winters with little snow cover and freeze-thaw
cycles. This is just the set of conditions which we get during an El Nino
winter and this is expected to be one of the worst in decades.
Vernon BC Zone 5