Turning Roots into Plants
15th February 2005

There is a simple and very effective way to increase your stock of some plants by propagating by root. The best and most scary examples are those of weeds. Chop up the roots of dock or bindweed and each piece will re-grow to become another weed problem. Fortunately the same principal can be applied to many trees, shrubs and perennials.

Propagation takes place when the plant is dormant. The ideal period is from late autumn to late winter. It is practical to dig up herbaceous perennials such as phlox and acanthus. Wash the soil off the clump and remove some healthy, young roots for propagation. At the same time the clump may be divided and replanted. With large trees such as Paulownia tomentosa it is best to dig for the young roots. In the case of the shrub chaenomeles take portions of young root from close to the centre of the root ball.

The ideal diameter of root is pencil thickness, although thicker can be used. Thin thread-like roots may also be used but are positioned differently.

Remove the roots from the parent plant using a sharp knife to make a clean cut. Store the roots in a polythene bag until you are ready to use them and, if the plant has been dug up, replace it as soon as possible. Firm it in and water to settle the soil around the roots.

Remove any thin side roots. It will be necessary to know which end of the root is the top and which is the bottom so cut the top of the root that was closest to the crown of the plant straight across. The base of the root cutting is cut at an angle. The sections of root should be 7.5-10 cm (3-4 inches) long. Dust the cut ends with Flowers of sulphur or a fungicidal powder to reduce the risk of fungal disease.

Insert the cuttings vertically, 5 cm (2 inches) apart in a moist, free draining, rooting compost with extra coarse grit added. The top (straight cut end) should be level with the surface of the compost.

Thin roots should be cut into 5-7.5 cm (2-3 inch) lengths and laid horizontally 5 cm (2 inches) apart on a seed tray of cutting compost. Lightly cover with the same compost and water the surface. Keep the cuttings in a cold frame or in a sheltered position outdoors over the winter months. In spring the cuttings will have produced more roots and the advantitious buds will have produced shoots and leaves. By summer the plants will be well rooted and may be potted into a compost with nutrients.

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