To thin them out and make them more tidy, you'll need to start by doing what you would do if you wanted to get rid of them altogether. You will have to dig everything out and then replant divisions of the rhizomes that were removed. You'll probably have a few stray pieces left in the soil that will put up shoots in the spring. You could remove them then or just let them grow.

If you cut off all the stalks and burn them after the first frost or cut them off and at least have them hauled away, you will be reducing the numbers of the the leaf rollers by getting rid of the eggs. I don't know much about dealing with leaf rollers because I never had any, but after the rhizomes have been dug out of the soil, maybe there is something you could apply there also before replanting.

For leaf rollers, release trichogramma wasps, or spray with BT (bacillus therengensis or something pretty close to that spelling!) in the spring.

Thanks for your advice. I have dug approx 30% so far... (I have a toddler, so it's difficult to apply so much time!)

If anyone wants some of these, please let me know.
laurenmarie@gmail.com

thanks!