Some sympodial orchids have a number of surplus eyes at the base, and further along the pseudobulb; usually those lower down are the strongest.
Many sympodial orchids can be propagated by removal of the oldest backbulbs – those pseudobulbs which have discarded their foliage and have become surplus to the plant’s requirements. Not all leafless pseudobulbs should be removed for this purpose as this may reduce the strength of the plant.
Ideally the plant should be left with at least four pseudobulbs, including those in leaf, on the main plant. The excess pseudobulbs can be removed by slicing them from the plant with a sharp knife. The cut should he made downward to sever the rhizome.
From the time of removing a backbulb from the plant, it can take about six weeks before any sign of growth movement is seen, and in some cases it can be considerably longer. Provided that the backbulb remains plump it may be left in the hope that it will eventually grow. It may even take up to a year before growth is seen.
During this time the backbulb should be kept just moist; an occasional spray over the compost surface will be sufficient until the new growth is seen. Even then water must be given sparingly until the new roots are seen. Roots follow growth, and the roots take up the moisture.
Monopodial orchids can also be propagated by various means, although it is not quite so easy, and usually comes about as a result of damage to the growing centre. Otherwise, with vandas and the like, only after several years’ growth is there a chance of propagating. l’halacnopsis are unique in the orchid family, and will propagate From the old flowering sterns.