From the plant's perspective, the primary function of a flower spike is reproduction. It is a specialized structure that elevates the blooms to attract pollinators, facilitate pollen transfer, and ultimately produce seed pods. This entire process is incredibly energy-intensive. Once the flowers have completed their lifecycle and fallen, the spike itself represents a significant investment of the plant's stored resources. The plant must now make a decision: should it continue to sustain this now-functionless structure, or should it reclaim the valuable nutrients and energy locked within it to fuel new growth?
In many Dendrobium species, particularly the nobile and hard-caned types, the old canes (pseudobulbs) that have produced flowers are not just one-time-use structures. They act as vital water and nutrient reservoirs for the entire plant. The green flower spike, even after blooming, can continue to perform photosynthesis, generating a small amount of energy for the plant. Furthermore, some Dendrobiums, like those in the Latouria section, have the potential to produce secondary blooms or "keikis" (plantlets) from the nodes on the old spike. By leaving a healthy, green spike attached, you allow the plant the opportunity to explore this secondary reproductive strategy. The plant will naturally begin to withdraw chlorophyll and nutrients from the spike, causing it to yellow and wither on its own timeline, ensuring efficient resource reallocation.
If the flower spike begins to turn brown, yellow, or dry out significantly, this is a clear signal from the plant that it has initiated senescence (programmed cell death) for that structure. A browning spike is no longer photosynthesizing and is effectively dead tissue. From the plant's viewpoint, a dead spike is a liability. It can become an entry point for fungal or bacterial pathogens that could threaten the health of the entire pseudobulb and, consequently, the plant. In this case, removing the spike is a protective measure. By cutting it off, you are assisting the plant in its natural process of jettisoning unnecessary tissue and helping to prevent disease. This action allows the plant to redirect its finite resources entirely toward developing new growths and a stronger root system.
When removal is necessary, the plant's health is paramount. Using sterilized pruning shears or sharp scissors is crucial to prevent introducing infection. The ideal cut should be made at the base of the spike where it emerges from the pseudobulb. Avoid cutting into the fleshy pseudobulb itself, as this creates an unnecessary wound. A clean cut close to the base allows the plant to seal over the wound efficiently. You may notice a small, dry scab form over the cut site, which is the plant's natural healing response. This precise removal mimics natural abscission and minimizes stress on the plant.
