I'm not sure how close to Jennifer this is, but the forecast for a week from now for Clinton, Michigan, is 21F for the high and 9F for the low. That's warmer than here where the high for that day is predicted to be 9F and the low -6F but still fairly cold. I've had a couple of daylilies survive down to 19F in pots by the house but I didn't risk lower than that and they'd been outside 24/7 up to that point. If a plant is not acclimated to significant cold it won't tolerate as much freezing as it would if it had been experiencing cold temperatures for a while and had time to adjust. (For example a daylily that can tolerate deep freezer level temperatures outside in winter, having adjusted during fall, will not survive being suddenly put in a deep freezer in July). I'm not sure how much cold acclimation a daylily in the garage would have developed, especially since it is growing, and it is, as Donald said, more vulnerable in a pot than in the ground.
