We know from a study that rust can be "latent" (not show any visible signs) for at least seven weeks after being exposed to spores, even though under ideal conditions it can appear within ten days or so, which is why I suggested above isolating new plants for a growing season to be on the safe side. I hope the freezing days have got rid of it for you, Pat - preferably it should have got cold enough to kill all the daylily leaves to the ground, otherwise there's a risk of the mycelium surviving inside them to erupt in pustules later on.
