Fall care for perennial kales in 6b?

This is my first year with perennial kales. I had about 10 grow from seeds. Now I need to know what I should do for them to get ready for the winter. All I've found online was mostly out of the UK and we get much harder winters here.

I typically would take all of the remaining leaves from my kales right before hard frost but I'm not sure if they should be left with the perennial ones.

One brief discussion I found mentioned taking cuttings for propagation  next year but didn't explain it all at. Anyone know anything about how to do that? ( I'd love to get more of them!)
Any advice welcome since I've been liking the leaf taste so far and really want them to carry on. Thanks!

I think you should not strip them bare before frost. A few leaves act as insulation for the crown and stems, and the plant can photosynthesize on mild winter days. Pile 4–6" of straw, shredded leaves, or compost around the root zone to buffer soil temperature and protect the crown. In colder zones, wrapping the main stem loosely with burlap, frost cloth, or even piling up extra mulch around the lower half of the plant can help prevent winter kill.