Here we cut leaves from the bottom up leaving the bud and a few leaves. Then hill them up with soil or compost. They will continue to root along the stem and grow from the bud. This way you can plant them and continue to harvest as they grow. The love nitrogen!
They are biennial so if planted in spring they will continue to grow all summer, fall and through winter. In spring as temps warm they will flower and set seed. By this time you can plant them again and start the process all over. They take heat and cold very well. We rarely get down to 10f, usually more like mid teens. If we do, it does not stay that cold for long at the time.
@Sally PB If any veggie can survive your winters, I'd say collards have a really good chance.