Answer: There's really no reason for your daylilies to deteriorate after you've divided them so I'd take a closer looks at the soil and growing conditions. Something is different since you replanted them. Perhaps the soil doesn't drain as well - or drains too quickly? Maybe your watering habits have changed. Is it possible that they were planted too deeply or not deeply enough? After 2 years they should have established themselves. I think it would be worth your effort to dig the plants up again, amend the soil with some compost to help it drain quickly yet hold just the right amount of moisture. Then replant and water well. I hope after they've been replanted they will thrive.
Best wishes with your daylilies!
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