The Orchid – Blooming in Cycles!

Most of the plants we cultivate are cyclical, which is not surprising since they have to cope with the cycle of the seasons and the alternation of day and night in the environment in which they grow. The sequence of changes that bring the tropical orchid to flower is very different from that of our native (more northern) plants. In fact, in the tropics, the days are more constant and the seasons less radically contrasted than in our latitudes. All of this will have a direct impact on the growing conditions we need to recreate.

Firstly, the Botanical Species in Their Natural Environment

Over the course of their long botanical evolution, orchids have adapted to their environment. They have gradually “specialized” in their ecological niche, making them relatively unique in terms of their growing requirements. Some have adapted to the cold conditions of the mountains, while others have learnt to grow in warm and humid conditions, such as by the sea. The light they need to grow can also be very different depending on the natural environment to which they have adapted.

Identify Their Growth Needs

This is the first challenge for anyone who wants to make orchids bloom: to understand their needs. As there are tens of thousands of botanical species in the world, it will be necessary to consult good sources to find your way around.

Most species of orchids that come from their natural environment (called botanical species) have a fairly strict growth and flowering cycle that is closely linked to their native environment. The cycle usually starts when the days get longer (winter and spring), first with the production of new roots, usually followed by the production of new leaves. As the days get shorter (summer and autumn), the plant changes its chemistry to begin tissue maturation. Under good growing conditions, this maturation should normally lead to the production of an inflorescence, flowering and finally, if necessary, seed production.

The Situation Is Less Clear for Hybrid Orchids.

The majority of orchids sold in stores are hybrids – the result of crossing species. Hybrids have many advantages in terms of quality and quantity of flowers. However, their growth cycle is less clear and less strict. Some hybridization specialists deliberately include non-cyclic plants in their crossbreeding programme to allow multiple flowering in the same year, so that they can market orchids that ‘flower’ at different times of the year – Christmas, Valentine’s Day, Easter, Mother’s Day, etc. This is particularly true of hybrid phalaenopsis, which can now be marketed all year round thanks to industrial production. 

Phalaenopsis Hybrids

This is particularly true of hybrid Phalaenopsis, which can now be marketed all year round thanks to industrial production. However, Phalaenopsis retain a certain periodicity that will ‘synchronise’ with your local growing conditions over time. You will have to discover this periodicity by observing its growth and flowering over a number of years. 

Don’t be surprised if you don’t see new roots for 6-8 months and/or if the flowering time is very different to when you bought it in flower. Industrial production environments can be radically different from your home – especially if the plants have been produced in Asia. Don’t worry, with “good horticultural care” they will adapt and resume their natural growth once they find their “climatic cues”.

Some orchids in the large Oncidium family have a puzzling cycle in which the production of new leaves precedes the appearance of new roots. I am still searching for an explanation for this botanical anomaly. If a reader can enlighten me on this subject, I would be grateful if they would share it with me in the comments section of this blog.

Care must also be synchronized with the cycle

In practice, it is essential to know where the orchid is in its cycle in order to cultivate it well. Each growing season requires specific care, which we will try to meet.

Here are some examples:

Root Production Season

• increase watering
• start fertilizing again
• make sure the light is strong enough
• repot the plant if the substrate has deteriorated

Leaf Production Season

• maintain the level of watering and fertilisation
• monitor the appearance of insects.
• new shoots are pruned if necessary

Ripening Season

• monitor the emergence of the inflorescence.
• nitrogen fertilisation may be reduced (too stimulating)

Flowering Season

• straighten badly oriented inflorescences
• support inflorescences that are becoming heavier
• place plant more prominently to enjoy it
• reduce the amount of sunlight.

After flowering, the orchid is usually given a period of rest by reducing watering and stopping all fertilizing. This is often the best time to prune the plant and remove old dying shoots (old yellowed leaves, old blackened roots and old browned pseudobulbs).

After a few weeks you will see new roots appearing, confirming that a new growing cycle is beginning.

A Few Practical Tips

Owners of large collections may find it difficult to remember the specific growing requirements of each of their plants. Some keep a ‘growing diary’, noting the times of year when new roots appear, when inflorescences form and, of course, the normal flowering period.

Personally, I prefer to stick a small label on each of my pots that succinctly summarizes the plant’s cycle. The first line is the name of the plant and the date of the last repotting, preceded by the letter “P:” (for potting). On a second line (or label) I write an ‘R’ for new root, an ‘i’ for inflorescence and an ‘F’ for flowering, next to the month of the year in which I observed the event. It’s clear, easy to read and very practical for adjusting my horticultural treatments.

Editor’s Note

Mr Charpentier’s columns on orchids are published on the Jardinier Paresseux website in a legal ‘copyleft’ framework. Horticultural societies wishing to do so may simply distribute the web link to their members or include his columns in their magazine. However, please include the following mention:

This article was originally published in French on the JardinierParesseux.com website and in English on LaidBackGardener.blog.