Wow. That's wicked strange. I hope its a mutation ("sport" wouldn't be the right term because that implies it appeared as an offshoot of another plant). Have the plants always done this? Are all the divisions from the one plant doing the same thing? And are any of your other plants NOT from this division doing it?

Do you see any signs of unusual insect activity, such as webbing that could have distorted the growth?

I'm thinking mutation, but then I'm obsessed with plant mutations.

Have you seen it bloom yet? Hope it was a controlled cross with some interesting parents. You could have something very unique on your hands.

Mary,
I had some weird DL fan activity this early spring. Some grew up weird.
We had the weirdest weather this spring! One week in the 80's then bam 2 days with 3 inches + of snow a couple days along with freezing weather some days then 70 the next day....well you get the picture? Anyway I did inquire about the strangeness of new foilage coming up. I was told to not worry about it, it would grow out of it and they were right....my plants are fine now that our weather has not had freezing temps this past month. I'm in zone 7 but I suspect zone 5 may experience these kinds of weather things so I think that is what is going on with your plant. You might want to see if you can find information about it on the AHS website.
Nancy

Looks like spring sickness. I had it in the spring you coulld cut them back or just wait and thay will snap out of it given time

Yep, with all the off and on weather here in the south this year, i dont think one of mine didnt do that. And it seems that every year i have one or two that do it whether the weather is crazy or not, one for instance is the good ole ditch lilly, the leaves always curl and get stupid, i always know which one it is in the bed just from the leaves.

G