As with any kind of plant, parts of an orchid will deteriorate with time. This is especially true of the stalk that produces the flowers. As parts turn yellow or brown, it will be best to remove them. Not only are old parts unsightly, but they can also provide a breeding ground for pests or plant pathogens such as fungi or viruses. Removing these old parts through careful pruning is not as difficult as might be expected, as with many things, timing is important, however.
It is generally agreed among knowledgeable orchid growers that the best time to prune is as the plant has just entered its dormant phase, during October or November. Cutting away dead parts at this time will cause the least amount of stress on the plant and pave the way for new growth in the coming year.
One of the first parts that can be pruned is the flower stalk. Once the flowers have faded and withered and the stem has turned yellow or brown, it can be removed. Because of the possibility of infection being transmitted to the orchid, make sure the pruning shears have been sterilized with alcohol, or use a new razor blade for the procedure. The old stalk can be cut back to about one inch from the main body of the plant. Removing the spent flowers as they deteriorate is also a good idea, but it should be done carefully so as not to injure any of the other flowers or buds. Sometimes taking off the old blooms will stimulate the orchid to produce more buds, and this can lengthen the flowering season.
Orchid ‘pups’, small, new orchid plants will sometimes form if the flower stalk is pruned away while it is still green. These pups should be left attached to the mother plant until you see that they have formed some roots of their own. At this point, the pups can be put into a separate pot. This is a good way to produce more orchid plants, especially if the parent plant is especially attractive, as these will be clones.
Besides pruning back the old flower stalk, it is also a good idea to removed dead or damaged leaves or stems as well. Removing old leaves or stems will often encourage the plant to produce new growth, and this type of pruning can be done at any time of the year, whenever necessary. As with any pruning done on orchids, make sure to sterilize the cutting implements before you use them on another orchid, to prevent infections being spread from one plant to another.
When the orchid is being pruned, prior to its rest period, it will be a good idea to check on the condition of the roots. It can sometimes be easy to overlook this chore, but it can be as essential as any other aspect of pruning. Healthy orchid roots have a pale covering on them and are springy. Roots that should be pruned away are often soft and brown or black, they will not have the resilience of healthy roots and getting rid of them will help the orchid make new ones once growth resumes in the spring.