Thanks for all the comments.
In reply to the above responses, I have used round up but not close to these plants. But with the wind in Denver ?? It is a possibility... However beginning in April last year, it got warm early, the spring flowers bloomed then we had two episodes of - 7 degrees below zero about 10 days apart! The daffodils and tulips got hit hard so it wouldn't be too hard to expect the growing iris were also affected.
I will watch these plants closely this year and if they do the same thing, off to the mulch pile they will go!
