You can make the cuttings any time now that they are dormant and the leaves are gone. If you plan on burying them, you will need to do it before the ground freezes. When you do it, stand them up, upside down so the rooting end is closer to the surface. In the spring the warming soil callouses them. It takes quite a while for them to callous since they rely on the spring sunshine to warm the soil to callous them. That's why they are calloused by other means a lot of times.