An orchid node is a specialized, dormant growth point capable of initiating new structures on the plant. This nodule is essentially an undeveloped bud protected by a small, papery sheath or bract. Nodes house meristematic tissue that can be activated to produce flowers, stems, or entirely new plants. Understanding how to locate and utilize these structures is fundamental for encouraging re-blooming and propagating many types of orchids. This allows growers to transform a single flower spike into a source of future growth.
Identifying Node Locations on Common Orchids
The location of nodes differs significantly depending on the orchid’s growth habit, which falls into two main categories: monopodial and sympodial. In monopodial orchids, such as the popular Phalaenopsis (Moth Orchid), nodes are found along the length of the flower spike. Each node appears as a small, triangular bump covered by a protective cap or bract, and these are the most common nodes targeted for manipulation.
On the main stem of a Phalaenopsis, dormant nodes also exist at the base of the leaves. These axillary buds are typically less visible and are sometimes activated naturally to produce a basal growth. Monopodial orchids grow from a single, upright stem, so their nodes are arranged sequentially along the vertical axis.
Sympodial orchids, which include genera like Cattleya and Dendrobium, exhibit a different growth pattern, branching horizontally via a rhizome. In these types, nodes are found on the thickened storage stems, called pseudobulbs or canes, rather than on a flower spike. For Cattleya and similar orchids, nodes are located at the base of the pseudobulbs, where new shoots or “leads” emerge.
Dendrobium orchids, which have cane-like pseudobulbs, possess nodes along the length of these canes. New flower spikes and plantlets, or keikis, can emerge from these nodes, often closer to the top of the cane. The plant’s overall architecture determines the placement of these growth points, requiring the grower to look low on the pseudobulbs or along the vertical canes rather than on the spent flower stalk.
Understanding Node Function: Keiki Versus Flower Spike
The dormant node tissue can develop into one of two outcomes: a new flower spike or a keiki. A keiki (Hawaiian for “baby”) is a plantlet that is a genetic clone of the mother orchid. Keiki formation is a method of asexual reproduction.
The direction of development is governed by the balance of plant hormones within the node. High concentrations of the plant hormone cytokinin promote rapid cell division and shoot formation, favoring keiki development. Specialized products like keiki paste contain high levels of synthetic cytokinin, such as Benzyl Adenine (BA) or Benzylaminopurine (BAP).
Conversely, a different hormonal balance, coupled with specific environmental cues, directs the node to form a secondary flower spike. Lower night temperatures, particularly a drop of 10 to 15 degrees Fahrenheit below the daytime temperature, commonly trigger flower initiation. This temperature differential shifts the plant’s focus from vegetative to reproductive growth.
While cytokinin paste encourages keiki growth, the final outcome is influenced by conditions. Warmer temperatures, especially when combined with hormonal stimulus, tend to favor keiki production. If the goal is re-blooming, the node can be stimulated by pruning the spike above it, which releases the bud from apical dominance. The plant should then be moved to a cooler location to encourage a flower spike.
Step-by-Step Activation and Post-Treatment Care
Activating a dormant node requires a careful, sterile approach. Sterilize all tools, such as a razor blade or scalpel, by wiping them down with rubbing alcohol. This step prevents the introduction of pathogens that could cause infection in the exposed tissue.
The first physical step is to gently remove the protective bract covering the dormant node on the flower spike. This thin, papery sheath must be peeled away or carefully cut off without damaging the tiny bud underneath. A toothpick, tweezer, or the tip of a sterile blade can be used to lift the bract, exposing the pale green or yellowish bud tissue.
With the node exposed, apply a small, pea-sized amount of the specialized growth paste, typically a lanolin-based product containing cytokinin, directly to the bud. Use a cotton swab or a clean toothpick for this application, ensuring the paste fully covers the exposed area. Avoid over-application, as excessive hormone is not more effective and can lead to stunted or deformed growth.
Following application, move the orchid to an environment that supports the new growth. Provide bright, indirect light and increase ambient humidity to at least 50% to 60%, often achieved with a humidity tray or humidifier. The temperature should be consistent and within the orchid’s preferred range, avoiding cool drafts or extreme heat fluctuations.
If the node develops into a keiki, allow it to grow on the mother plant until it is self-sustaining. The keiki is ready for separation when it has developed three or more leaves and a root system with at least three roots that are each two to three inches long. Using a sterile cutting tool, detach the keiki by cutting the flower spike about one inch above and one inch below its base. Dust the small wound on both the keiki and the mother plant with cinnamon or a fungicide to seal the cut and protect against infection before potting the new plantlet.