The Terminal Spike on Phalaenopsis – What It Is, Why It Appears, and What You Should Do. Between Myth and Reality

Introduction

Probably all amateur growers of orchids from the Phalaenopsis genus have faced the “nightmare” of terminal spikes at some point. And, as in any online environment where expert opinions are often outnumbered by those based solely on limited personal experience, the orchid growing community is no exception to this phenomenon.

Although in very rare cases it may mean the end of the life cycle, most Phalaenopsis specimens with a terminal spike deteriorate due to growing conditions. Some enthusiasts mistakenly consider them lost plants from the start, completely ignoring their potential.

To have a justified opinion, it is necessary to gradually address some essential questions.

What are terminal spikes?

A terminal flower spike is the emergence from the central vegetative growth area of a bud that will develop into a flower. More precisely, in the leaf crown area, instead of a new leaf, a flower spike appears.

This aspect is known in orchid species with monopodial growth (such as Phalaenopsis). In monopodial species, there is an apical dominance, hormonally controlled, which suppresses the development of lateral buds. If a flower spike appears instead of a new leaf, the plant stops leaf growth in that direction.

However, this does not mean the plant will die. The cancellation of apical dominance usually activates the development of lateral buds through plant hormones (cytokinins). This phenomenon is also observed with keiki paste treatments or even when the terminal bud is accidentally destroyed.

It is important to remember that the dormant buds of Phalaenopsis species have developmental versatility: they can form either vegetative buds (keiki) or floral buds. The appearance of terminal spikes is more frequent in varieties that also have a high capacity to produce keiki.

What triggers the appearance of terminal spikes?

The appearance of terminal spikes is caused by the conversion of the vegetative bud into a floral bud and can have multiple causes:

• Physical – mechanical decapitation (accidental or intentional);
• Chemical – excessive application of antifungal, antibacterial, insecticidal, or miticidal treatments;
• Biochemical / physiological – naturally induced (at plant maturity) or artificially (by administering cytokinins).

Ultimately, all these causes lead to the production or accumulation of cytokinins, which activate lateral buds and trigger keiki formation. Some varieties are more prone to this phenomenon, and those same varieties tend to produce more keiki naturally.

What effects do terminal spikes have on the health and development of plants?

Although flower spikes naturally appear in basal or lateral positions, they can also emerge in an apical (terminal) position. Usually, this phenomenon triggers the appearance of basal plantlets (keiki), as the plant will no longer grow taller but will continue to function normally biologically.

In many cases, the appearance of a terminal spike indicates that the plant has reached maturity and will stop upward growth. However, numerous cases are known where plants continued to grow after the flower spike dried out.

One certainty is that a plant with a terminal spike will very likely produce at least one basal keiki. The ability to form keiki varies depending on species, variety, or hybrid.

Example of Phalaenopsis with terminal spike and basal keiki

What should you do when a terminal spike appears?

When you notice a terminal spike on a Phalaenopsis, the most important thing is not to panic. The plant is not lost. Here’s what you can do:

• Do not cut the terminal spike immediately. Let it dry naturally. Premature cutting can unnecessarily stress the plant.
• Ensure stable conditions of light, temperature, and watering. A stressed plant will produce keiki with more difficulty.
• Wait for the keiki to appear. In most cases, the plant will generate at least one basal keiki in the following months.
• Keiki appearance can be stimulated by applying keiki paste on the dormant buds at the base if you want to speed up the process.
• Repotting can be done if the substrate is degraded, but it is not mandatory immediately after the terminal spike appears.

For general care conditions of your Phalaenopsis (temperature, watering, fertilizing, substrate), read the complete guide: Phalaenopsis Care | Complete Guide for the Butterfly Orchid.

Phalaenopsis with completely broken middle – generating keiki, flowers, and new roots

In conclusion, the appearance of a terminal spike does not mean the end of the plant. It is a natural phenomenon in many mature Phalaenopsis, and the plant usually responds by producing keiki, thus continuing its life cycle.