Now is the Time!
Nearly everyone takes stem cuttings as some point, but surprisingly few gardeners bother with root cuttings. Some useful plants can be propagated this way, and it is an interesting and relatively simple winter job, because root cuttings are only likely to be successful if taken during the dormant season.

Lift a young but well-established plant to provide the cuttings. If you don’t want to use the whole plant for cuttings, and prefer to leave the parent plant largely undisturbed, just remove soil from one side to gain access to the roots. If the plant has large, fleshy roots, cut off some that are close to the main stem or root. You should be able to make several cuttings from one root by cutting it into sections later.

Cut each root into lengths about 2 inches long. To help you remember which way up they are, cut them horizontally at the top and diagonally at the bottom. Fill the pot with a gritty potting mixture and insert the cuttings using a dibber or pencil to make the hole. The top of the cutting should be flush with the top of the potting soil.

Sprinkle a thin layer or grit over the surface. Label, as nothing will be visible for a few months, and it’s easy to forget what the pot contains. Place in a cold frame or greenhouse and keep the potting soil just moist.

Some plants, such as border phlox and rock plants like Primula denticulata, have thin roots. These can be laid horizontally, so don’t make sloping cuts to indicate the bottom. Just cut into 1-2 inch lengths. Fill a seed tray with gritty compost and firm it level.

Space the cuttings out evenly over the surface, then cover them with a layer of the gritty potting mix. Keep moist but not too wet, in a cold frame or greenhouse.

Some good plants to grow from cuttings are: Acanthus, Echinops, Gaillardia, Phlox (border), Primula denticulata, Pulsatilla vulgaris, and Romneya coulteri.