The Phalaenopsis, commonly known as the Moth Orchid, represents the vast majority of orchids found in homes and stores due to its long-lasting flowers. After the display of blooms fades, a frequent question arises about the fate of the “stem,” botanically known as the flower spike. Whether this structure can produce new flowers depends entirely on the specific type of orchid and the condition of the spike itself.
How Reblooming Happens on Old Stems
For the Phalaenopsis orchid, reblooming on the original spike is possible, provided the spike remains green and firm. The flower spike is dotted with small, triangular bumps called dormant nodes, which are undeveloped growth points protected by a thin sheath. These nodes are the plant’s reserve of potential, each capable of developing into a secondary branch of flowers.
A node activates when the plant is healthy and the main bloom cycle has ended, especially after the top portion of the spike is removed. Once triggered, the node swells and produces a lateral side shoot that develops new flower buds. Less commonly, a node can be stimulated to produce a keiki, a fully formed clone complete with roots and leaves. A green, living spike indicates that vascular tissue is still transporting water and nutrients, making it a viable candidate for a second round of blooms.
Pruning the Spike for Future Blooms
When the last flower drops from a viable Phalaenopsis spike, the grower has two primary pruning choices that affect the next bloom cycle. The first option is to encourage a faster, secondary rebloom by cutting the spike high, just above a dormant node. This method involves locating the second or third node from the base and making a clean cut approximately one inch above it using sterilized cutting tools.
Cutting the spike high channels the plant’s energy into activating that nearest node, often resulting in flowers within a few months. The trade-off for this speed is that the secondary spike produces fewer and slightly smaller flowers than the original display. The second choice is to cut the entire spike low, near the base of the plant, which encourages the orchid to initiate a completely new, stronger spike from the crown.
While cutting low results in a longer wait, often six months to a year, the new spike is robust and capable of producing a fuller array of blooms. Using a sterilized razor blade or shears is necessary to prevent the introduction of pathogens into the orchid’s tissue. This decision comes down to prioritizing either a quicker floral reward or a more vigorous display later on.
When the Old Stem Must Be Removed Entirely
The old flower spike must be removed completely if it is dead or if the orchid’s growth habit dictates removal. For the Phalaenopsis, if the entire spike has turned brown, yellow, or mushy to the base, it is no longer viable and should be cut off entirely. A dead spike serves as an entry point for disease and will never rebloom, so it must be severed close to the crown of the plant.
Many other popular orchid genera, such as Cattleya, Dendrobium, and Oncidium, will not rebloom from their old flower structures. These are known as sympodial orchids, meaning they grow horizontally and produce flowers from structures called pseudobulbs or canes. Once the flower spike on these pseudobulbs has finished its bloom cycle, the cane is spent and will never flower again.
For these sympodial types, the entire flower spike or cane should be removed at the base once it has yellowed or dried. This allows the plant’s energy to be redirected to developing new growths. Removing the spent structure is necessary to allow the next season’s growth, which is responsible for the future bloom, to develop unhindered.
Environmental Needs to Stimulate New Spikes
After the post-bloom rest period, the primary trigger for a healthy orchid to produce a new flower spike is a precise shift in its environment. The most effective cue is a consistent temperature drop between day and night, mimicking the change of seasons in their natural habitat. Phalaenopsis require nighttime temperatures to be approximately 10 to 15 degrees Fahrenheit cooler than the daytime high for several weeks to stimulate spike initiation.
Daytime temperatures should remain moderate, around 70 to 80 degrees Fahrenheit, while cooler nights should dip to about 60 to 65 degrees Fahrenheit. This temperature differential signals to the orchid that conditions are right for flowering. Simultaneously, the plant must receive adequate bright, indirect light, which is necessary for the photosynthesis to fuel spike development.
During this rest and spike-triggering phase, growers should also adjust their fertilization routine. Switching to a formula with lower nitrogen and higher phosphorus is beneficial, as nitrogen encourages leafy green growth, while phosphorus supports the development of roots and flowers. Providing these specific light, temperature, and nutrient cues ensures the orchid has the energy and biological signal to produce a new, robust flower spike from the base.