I didn't divide my daylilies last year, and as thye are coming up this year I am noticing how crowded the poor things are. Will I hurt them if I divide them in a couple of weeks (when the ground is completely thawed)? I am new to my garden - it came with the house we bought last year, but I was pregnant all last summer so I didn't get much done - and I have tons of daylilies and they all are in need of division.
I'm not an expert - but I divided mine in the spring for the same reason as you want to divide them, and not only did they survive, but they bloomed like crazy - just getting a little more room seemed to give them great incentive. I've found, if you are careful and water water water, you can move most anything any time. It's not always what you SHOULD DO WHEN, but what you CAN DO NOW. Most plants are pretty forgiving, with a little care.