Plant cuttings are by far the most usual way to raise plants at home. The chance of success depends on the variety – some woody plants are difficult or impossible to propagate without special equipment, whereas several popular plants, such as Tradescantia, Impatiens and Ivy, will root quite readily in a glass of water. Even with easy-to-root cuttings there can be inexplicable failures so always take several plant cuttings and do not be disappointed if a few of them fail.
Leaf cuttings. Some plants do not have stems; the leaves arise directly from the crown of the plant. Obviously stem cuttings are impossible, but leaf cuttings provide an easy way to propagate many of these varieties.
Stem cuttings. Most house plants can be propagated from stem cuttings. Choose a sturdy and healthy non-flowering shoot. Some non-woody plants will root at any time of the year but woody varieties are generally more reliant on active growing conditions so in this latter case always follow the timing and always use a rooting hormone.As a general rule spring or early summer is the best time for all plants, but late summer is a popular time for striking Fuchsia and Geranium cuttings.
Stem cuttings should be inserted in the compost as soon as they have been prepared, but a cactus or succulent cutting should be left to dry for several days before insertion.
Plant cuttings: Geraniums
Cane cuttings. A number of important plants which produce thick and erect stems are propagated by means of cane cuttings. The best time to do this is when one or more stems have lost their lower leaves and are no longer attractive. The bare trunk is cut into several pieces, and each piece is inserted into seed and cutting compost. The cane cuttings can be placed horizontally, as illustrated, or planted upright. If planted upright, make sure you bury the end which was the lower part on the stem. Cane cuttings can be used for Cordyline, Dracaena and Dieffenbachia.
How to root cuttings?
The problem your cutting has to face is obvious. It will usually be a severed piece of stem or leaf, and it will steadily lose moisture without having any means of replacing the loss.
1. The rooting bag method. A recent innovation is the rooting bag, in which seed and cutting compost is tightly packed and sealed in a stout polythene bag. There are two basic advantages compared to the pot method – the covered compost stays moist much longer and weak cuttings are supported by the polythene. The method consists of cutting 14 slits in the upper surface and inserting a cutting through each slit. If the cuttings wilt after a few hours, the rooting bag is slipped into a large plastic bag which is blown up and the top tied with a wire tie or self-adhesive tape.
2. The propagator method. A propagator is a useful piece of equipment if you intend to raise a large number of plants. Basically it consists of a firm tray to hold the compost and a transparent cover which bears air vents. A simple unheated model will meet the needs of the average indoor gardener, but if you plan to raise delicate plants which need a propagating temperature of 70°F or more then you will need a heated propagator.
3. The pot method. A 5 in. clay or plastic pot will take 3 to 6 average-sized cuttings. The rooting medium must be sterile, free-draining, firm enough to hold the cuttings and contain not too much fertilizer. A specially formulated seed and cutting compost is ideal. Fill the pot with compost and lightly firm to leave a ½ in. watering space at the top. The cuttings should be inserted close to the side of the pot; make sure that they are properly firmed in as an air space around the cut surface is fatal. Some cuttings are inserted vertically and others at 45°. Water in very gently.
Nearly all cuttings will need a humid atmosphere – in dry air large leaves soon shrivel and die, as there is no root system to replace the rapid loss of moisture. Place four canes in the pot and drape a polythene bag over them; secure with a rubber band. There are 3 important exceptions to this polythene bag technique – do not cover cactus, succulents or geranium cuttings!
Place the pot in light shade or in a bright spot out of direct sunlight. The temperature should be 65°F or more. Pick off any leaves that turn yellow or start to rot.
The great enemy now is impatience – do not keep lifting the cuttings to see if roots are appearing. In a few weeks the tell-tale signs of success should appear; new growth at the tips of stem cuttings, and tiny plantlets at the base of leaf cuttings.
Potting-on time has arrived. Water the compost and then lift out each rooted stem cutting, taking care not to disturb the compost around the roots. Transfer each cutting to a 2½ or 3½ in. pot – fill with potting compost. Firm gently and water to settle the compost around the roots. Put the pots back in the same spot for a week or two; then transfer to their permanent quarters.