As a propagator there is not much to do at this time of year, except planning for the upcoming season of course. So that's why root cuttings are an important propagation technique to help spread your work load throughout the year, as whichever plant you can take a root cutting from you can probably take a cutting or collect seed from but those are usually busy times in the year, so you might as well leave it for a winter job.

The other benefits of doing root cuttings is avoiding pest and disease that might be in the plant during the growing season, you can get a lot of material from just one plant and they are easily maintained; just place in a cold frame (somewhere out of excessive winter rain and wind), keep moist and wait for new shoots and roots in spring.

Herbaceous plants you can do root cuttings from: Phlox, Echinops, Alcea, Papaver orientale, Anemone, Asclepias, Astilbe, Eryngium, Kalimeris and Paeonia as examples.

Shrubs you can do root cuttings with (any that sucker): Syringa, Rosa, Rubus, Ficus, Rhus and Campsis as examples.