Orchids can be propagated vegetatively like many other plants, whether from back bulbs, stem cuttings and keikis or adventitious growths. In many cases, the method of propagation depends on whether the orchid is sympodial or monopodial. The monopodial orchids, such as vandas, are those that grow from an upright, extending rhizome, with new leaves coming from the centre. These orchids propagate themselves, or can be propagated from, in a different way to sympodial orchids.

Phalaenopsis occasionally produce keikis or adventitious growths from the old flowering stems. This is frequently seen with the species Phalaenopsis lueddemanniana and related species or hybrids. If you want to encourage new growth in this way, you can treat the flowering stems with keiki paste – a growth hormone enhancement that is available from some specialist nurseries or orchid sundry firms. First remove the small green bract that protects each node along the stem, then apply the paste.

If the treatment is successful, a new plantlet will grow, producing its own leaves and roots, which can be removed and potted up when large enough. Vandas orchids are monopodial orchids, but they are not so easy to propagate from.

Cattleyas are sympodial orchids that are also treated slightly differently. The creeping rhizome is much thicker than that of other orchids and is visible on the surface of the compost with the pseudobulbs spaced along it. Most cattleyas have two growing seasons in any year, producing new growth and roots in the autumn as well as in the spring. This makes it possible to start propagation during the autumn by severing the plant, which remains in its pot.

You can cut through the rhizome with a sharp pruning knife to separate one or two of the oldest pseudobulbs, then leave them undisturbed until the following spring. By this time, these back bulbs should be showing a new growth, and when the plant is repotted, they can be potted up on their own and grown on in the usual way. Alternatively, this is also a good way of getting a Cattleya to make extra growths, if you want to build up a specimen-size plant.

The majority of sympodial orchids with pseudobulbs can be propagated in this way, but there are exceptions, such as orchids from the Odontoglossum alliance. It is always worth potting up any spare back bulbs and growing them on to flowering, although this can take a few years.

Do this before cutting off the top portion of the plant, which will not succeed otherwise. 0 Cut lengths of stem at least 25cm ( I Oin) long from the plant (in this case Dendrobiwn nobile), cutting just above a node (growing point). It can take as much as 12 months before any new roots are seen, and this process is not guaranteed to be successful.

Alternatively, you can take stem cuttings from orchids such as dendrobiums and thunias by laying stem lengths on their sides in a seed tray. A new plant will emerge from the node in a few months. Again, this is a longterm procedure and is only worth doing if you want a number of young plants identical to the main plant.