Orchids generally cannot be grown from a simple cutting like a rose or common houseplant. They lack the standard botanical structures necessary for traditional stem cuttings to succeed. Instead, propagation involves specialized methods of asexual reproduction, which separate established sections of the parent plant. The specific technique used depends entirely on the orchid’s growth habit, but the result is always a genetic clone of the original.
Why Standard Stem Cuttings Are Ineffective for Orchids
The fundamental barrier to traditional cuttings lies in the unique morphology of the Orchidaceae family. Most common plants that root from cuttings possess distinct stem nodes containing pre-programmed buds. Orchids, however, do not share this characteristic in their main growing structures, rendering a simple stem cutting ineffective.
Orchids fall into two growth types. Monopodial orchids, such as Phalaenopsis (Moth Orchid), grow vertically from a single main stem. Cutting this primary stem removes the plant’s single growing point, which is often fatal to the lower section. Sympodial orchids, like Cattleya and Dendrobium, grow horizontally via a creeping rhizome, producing thickened storage organs called pseudobulbs. These pseudobulbs store water and nutrients. Cutting a pseudobulb without sufficient accompanying roots and bulbs will starve the section, preventing it from forming a new plant independently.
Specialized Asexual Propagation: Keikis and Flower Spike Sections
Monopodial orchids, which cannot be divided, rely on specialized plantlets called keikis for propagation. A keiki is a genetically identical clone that develops from a node on the flower spike or occasionally from the base of the plant.
A keiki is ready for separation only when it has developed its own root system, typically with at least two or three roots that are two to three inches long. To separate a keiki, use a sterilized cutting tool to remove the plantlet, taking a small section of the mother spike with it. The new orchid is then potted into its own container.
Flower Spike Sectioning
A less reliable method involves sectioning a spent Phalaenopsis flower spike between the nodes. Each section, containing a dormant bud, can be placed on moist sphagnum moss in a high-humidity environment to potentially stimulate new growth.
Specialized Asexual Propagation: Division of Sympodial Structures
The primary method for multiplying sympodial orchids, such as Cattleya, Cymbidium, and Oncidium, is through physical division of the rhizome. This process is only possible when the orchid has reached a substantial size, generally with at least six to eight pseudobulbs. Division must be performed at the rhizome, the connecting stem that runs along the potting medium surface.
The rule of thumb for successful division is to ensure each new section has a minimum of three to four connected pseudobulbs. These older pseudobulbs, often called “back bulbs,” hold the necessary energy reserves to sustain the new growth. After making a clean cut through the rhizome with a sterilized blade, the cut surface of both the mother plant and the division should be treated immediately with a fungicidal powder, such as cinnamon or sulfur, to prevent rot.
Post-Propagation Care and Establishment
The success of any orchid propagation method relies heavily on careful post-separation care to encourage establishment. Newly separated keikis or divided sections are vulnerable because their root systems are often immature or damaged.
New plants should be placed into a fine-grade potting medium, such as sphagnum moss or fine bark, to provide necessary moisture retention and aeration. Maintaining high ambient humidity is crucial during this vulnerable period, often achieved by placing the pots inside a humidity dome or clear plastic bag. The new propagules should be situated in bright, indirect light, avoiding direct sun exposure. Water should be managed carefully, keeping the potting medium lightly moist but never saturated, which promotes new root growth.