Plant Propagation Techniques – Root Cuttings
Plant Propagation Techniques
There are several different plant propagation techniques and this article will cover how to propagate plants using root.
Some plants, both herbaceous and woody, readily produce shoots direct from their roots as a natural process, particularly at a point where damage has occurred. Consequently, pieces of severed root can be used as cuttings. Root cuttings require less attention than semi-hardwood or softwood cuttings.
Shrubs that grow well from root cuttings include sumach (Rhus), smoke bush (Cotinus), spiraea and ornamental brambles (Rubus). Lift the entire plant any time from autumn to spring, using a garden fork, or unearth part of the root system of a large plant. Then, with secateurs, cut off the thicker roots close to the main stem or root.
Cut each piece straight across the top (nearest to the main stem or root), and at an angle at the base — this will help you to remember which way up to plant them.
Perennials can also be increased from root cuttings which have been taken during the dormant season. Thick and fleshy rooted plants, such as bleeding heart (Dicentra), oriental poppy (Papaver orientale), anchusa and Californian tree poppy (Romneya) are particularly suited to this method of propagation.
Lift the plants in the autumn and cut healthy roots into 5-7.5cm (2-3in) pieces, making a straight cut across the root nearest to the crown, and a slanting cut at the other end.
Fill pots to a level just below the rim with a proprietary potting, and make planting holes in the compost to the same depth as the cuttings, using a small dibber or an old pencil.
Insert the cuttings, straight cut uppermost so that the top is level with the surface of the compost. A 12cm (5in) pot will usually accommodate about six cuttings. Cover the cuttings with about 6mm (1/4in) of coarse sand, and spray them with water.
Fibrous-rootedare often increased from root cuttings; it is a method used particularly for the perennial phlox to prevent incidence of the dreaded stem eelworms.
Lift the plants during dormancy and cut the selected roots into short pieces about 5cm (2in) long — it is not necessary to distinguish between the top and the bottom of the cuttings. Lay them flat on the surface of a box which has been filled with John Innes seed compost, and cover lightly with sand.
All types of root cuttings should be kept in a cold greenhouse or closed frame during the winter. By spring, the cuttings should have rooted well and begun to develop leaves.
Knock them out of their pots and separate them carefully before potting them up individually in 7.5cm (3in) pots filled with a proprietary potting compost, or alternatively they could be planted out in lines in an outdoor nursery bed.
By the autumn, the young plants should be sturdy enough to be moved to their permanent quarters in the garden.
Other plant propagation techniques include: