And there it is right there: "we had a warm spell in February followed by cold weather until last month."
Confused plants produce confused flowers. If you lived where it was colder, you would worry about warm/cold spells because your daffodil and tulip flowers would be stemless. Its a weather thing. They will be fine when (if) the weather ever gets back to "normal"
Even though the daylily right next to the "runt" is fine, the flowers developed at different times. Later flowers on the short stemmed plant should develop at the usual height.
Unless you have a personal relationship with the weather gods, there's not much you can do.
