Most people know about taking cuttings, or slips, of the stems of plants but not so many know about root cuttings. But this is a very easy and successful way to take cuttings and raise new plants. It was once used a lot by traditional nurseries but it can be used in a home garden just as successfully.

The principle is simple: lift some roots of suitable plants and cut them into smaller pieces, each of which will give rise to a new plant. It is so reliable that practically every piece of root develops into a small new plant.

The technique is used for perennial flowers, shrubs and even some trees. All of the suitable plants have thick roots that act as storage organs for plant nutrients and sugars, and can supply these to form a new plantlet. Some kinds have a tendency to produce suckers from the roots, but this is not true of most.

Perennial flowers that are suitable include: Japanese anemone, bears breeches or acanthus, verbascum, Oriental poppy, some kinds of primula, echinops and phlox. Anybody who has grown these clump-forming flowers and who has dug out these kinds, perhaps to move them, may have found that they re-constituted themselves from pieces of root left behind when lifting.

Shrubs and trees that can be raised from root cuttings, often re-establishing from roots left behind when a plant has been lifted, include lilac, robinia, catalpa, poplar, willow, clerodendrum, chaenomeles, embothrium, solanum, sumach, aralia, passionflower, clethra and some kinds of camellia, notably the Williamsii hybrids.

While the poplar and willow will grow from any bit of root, trunk or branch, the others are not so amenable, such as robinia and sumach, to rooting from stem cuttings, but both are enthusiastic producers of root suckers.

To raise any of these plants from suckers, it is first necessary to get access to the roots. In the case of perennial flowers, it might be possible to dig out the whole plant, knock off some of the loose soil and reveal the roots. The thickest roots can then be taken off the rootball, allowing enough for the quantity of plants to be raised.

Root cuttings of herbaceous perennials can each be made about 5cm to 7cm long. For shrubs and trees, more root material is available and the cuttings can be made bigger. It is not necessary to dig much, just enough to get access to some good strong roots will do.

To make the cuttings, cut away the thin end of the root and cut the remainder into pieces of suitable size. Cut straight across the “plant-end” of the root and make a diagonal cut across the “root-end” so that when they are inserted in pots or trays, the cuttings are right-side up. For types that have thin, flexible roots, like Japanese anemone, leave them longer, as these can be laid horizontally.

Prepare enough pots or trays to take the cuttings inserted about 5cm apart. The compost can be multipurpose compost with some coarse sand, perlite or vermiculite added to ensure plenty of air can reach the cuttings. Insert these to their full depth and cover with a layer of vermiculite or similar.

This layer helps to stop the cuttings drying out. Water after insertion, and as necessary, but sparingly after that. Cuttings of some of the stronger trees can be inserted in the open ground outdoors and their position marked.

The cut ends soon seal off and the tops develop little green buds from which new shoots arise in spring. At the same time, new roots grow from the root cutting. When well established, the new plants can be potted up and grown on.