There are many things that we, as orchid growers take for granted. How many times have we heard phrases like "I find that species so easy to bloom" or "She grows that plant so well, but it's impossible to flower". What is it that determines the how, why, or when behind a plant's blooming?
Plants do not have the benefit of calendars to determine the best time to bloom. Nature has therefore provided ways to control the release of flowering hormones at the appropriate time before the blooming season. These controls, or hormonal release triggers (as they are better known) are activated some natural phenomenon or environmental trigger).
{{Side Note: Actually, when we speak of triggers, most often we are referring to environmental triggers. Few of us are schooled sufficiently in biochemistry to easily remember the names of the actual hormones, let alone their pronunciation.}}
The natural phenomenon must be obvious enough to stimulate the majority of plants in a natural population. In this manner, the trigger acts much like a choreographer in orchestrating the coordinated flowering of a given wild population.
There are several advantages to the majority of plants blooming at the same time. Natural pollinators will visit manyflowers, hence ensuring the genetic diversity and stability so necessary for the survival of a wild population. With the increase in pollinator activity, more plants are likely to set fertile seedpods.
Nature, in her network of delicate balances, has choreographed every minute detail of her dance. Her flowering seasons coincide with the most favorable weather in that locale. This ensures the least obstacles to the pollination process. Other factors that pertain to this chronological aspect of triggers are speciation and duration of pod ripening, but these are beyond the scope of this introduction.
Earlier, we mentioned that a trigger was associated with an obvious environmental factor. By "obvious" we mean that ideally, the natural phenomenon is significant enough, that it will not be accidentally activated at the wrong time. Some real examples are marked increase or decrease in day length (referred to as photoperiodism) or a fluctuation in an aspect of temperature (a shift in the average daily, rise in daily high, or drop in nightly low etc.) Often there are several factors that are required to occur in conjunction to activate the trigger. This lessens the possibility of an accidental activation. For instance, let's consider reduced water, increased light and a marked drop in the night temperature. At first glance these three characteristics might seem unrelated and unlikely to coincide easily. At least until we examine the effects of an absence of cloud cover. The first obvious result is an increase in light intensity, since there is nothing to block the sun. Without clouds there can't be rain, hence a dry spell begins. At night the clear evening sky results in a greater drop in night temperature than is customary because clouds serve as insulation.
In conclusion we have established how a single natural event can lead to several coincident environmental changes. In fact, this trigger actually does occur in the Philippines for a four to six week period every autumn. One group of orchids that is then activated is the euphalaenopsis section of phalaenopsis, which flowers almost exactly 90 days later! One important point to remember is that each trigger is specific to that particular microenvironment. In other words, when studying a species whose natural habitat is widespread, we find variation in the triggers over the area of distribution. This reinforces the specificity or a natural trigger, and it explains why some plants of one species are more easily flowered than others (even though they seem superficially identical). This also helps explain why growers in one region will have such good luck with certain genera and such poor luck with others. At least this is the excuse that I prefer to use; the mystical quality helps to make it all the more convincing!
What we must attempt to do in captivity is to replicate the natural conditions that trigger the flowering of our more reluctant bloomers. For this reason, it is very important to possess as many details about the climate in every orchid's habitat. My pursuit of these elusive truths has led me to respect immeasurably the collector who includes the annual climate chart pertaining to a plant's locale.
Often the finer details of the environment that may serve as a trigger are overlooked by the casual observer. An example that comes to mind is my frustration over Paphiopedilum rothschildianum. Finally light was shed on my dilemma when I happened upon an article that mentioned some unusual particulars of the habitat.{1} If you have access to this article, I strongly recommend reading it carefully so you can catch a glimpse of the intricacies that come into play in a plant's natural life cycle in the wild. I will attempt to do justice through a brief synopsis, for those of you that do not have access to this article.
Roths grow wild on Mount Kinabalu in North Borneo. During the winter season, a change in wind direction allows the cold air from the peaks of Kinabalu to course down the rain gullies that extend to the base of the mountain. This sudden cooling in an otherwise warm habitat, stimulates the blooming of mature plants some three to four months later. This seems straightforward enough, but only the plants subjected to the sudden cold snap will flower. This means that all the flowering plants are either at the edge of the cliff or on the gorge walls! Hence their existence there is tenuous, at best. The fierce rains will inevitably dislodge these plants sooner or later through erosion.
Now we begin to formulate an idea of the dynamic cycle these plants go through. The seeds must ripen and disperse before the parent plant dislodges, or else they are lost. A mature plant's flowering lifetime is likely limited to five years at best. (There are genetic pool implications here, but again, beyond our present scope.) The dispersed seed must land far enough from the gorge that the seedlings will each flowering size before erosion brings them to the cliff face. Hence, it becomes a great race between growth, erosion and time. As if this were not enough, there is also an elevation limitation at play. The seedlings that grow too low will not experience a sharp enough fluctuation in temperature since the cold air warms as it descends, hence they will not be triggered to flower. The seedlings that grow at the upper elevation limit, face too cool a standard environment and hence struggle to stay alive. Thus Roths are effectively restricted to a narrow band of elevation in their wild habitat.
There are many more fascinating examples of triggers in the orchid world. You almost become a detective by researching and analyzing the data of the plant habitats. I can only speak for myself when I say that this is one of the things that keeps me intrigued by orchidology. Only through examining these fine aspects of nature can we really admire her beauty, appreciate her complexity and respect her tenacity.
{1} Fowlie, J.A., M.D. and Tony Lamb 1983. Malaya Revisited. Pages 175-182 in the Orchid Digest 47:5.
Claudio Rossi
Since a number of visitors to my greenhouse have not heard of this old trick I thought it might stand repeating. To catch slugs, snails and other crawlies in your orchid pots, place slices of potato with the underside slightly hollowed on top of the compost. The undesirables like to hide under the potato and are easily collected and squished or fed to the turtles or fish. The slices can be left for two or three days and can be inspected as often as you have time....you may be surprised at what you find!
No poisons, no protective clothing needed !
Annette
I hope the growing season was better in your area than in ours, June was very cloudy and wet so most things in the greenhouse are at least one month behind. I guess that makes up for the great weather we had before the congress last April, which allowed so many of us to exhibit such wonderful flowers.
Please let Annette know who your new executive are when your elections come up as we would like to send our literature to the most current people in your orchid groups. Particularly your Canadian Orchid Congress representatives. If you do not have one already please get one soon, as we would like to start contacting these people as to the various functions your orchid groups are having. We particularly would like to know when your shows are going to be, who the contacts are and the theme, if there is one. So please send that information in and we will publish it so that the rest of Canada knows what is happening where and whom to contact.
There have been several requests for the COC to strike a pin, so for the first issue we are going to have our logo made into a pin. We hope to have these available before Christmas '91. Price is not known at this time but we hope it will be in line with most other pins of this sort.
Ray Bilton from McBean's Orchids in Sussex, England will be touring across Canada speaking at various orchid societies on his way. If your group was fortunate enough to get Ray to come and talk, we hope you will enjoy him. The plant list was quite good so we can look forward to adding all sorts of new treasures to our orchid collections. I would like to thank Howard Ginsberg from Montreal for arranging this trip. It takes a lot of hard work and dedication to see such a project through. Again thank you Howard, your work is greatly appreciated.
Unfortunately due to several obstacles, the trip to Central and South America has been cancelled. The cholera outbreak and political problems of these countries made it quite difficult to put together such a trip. Thank you Carl Withner for your work on this trip, hopefully there will be another opportunity in the future to arrange such a trip, maybe to Brazil in '96 for the World Orchid Conference. I would also like to thank all of the people who put their names forward for this trip.
Are there any orchid videophiles out there? The COC is looking for people who would like to write, produce, film and star in their own orchid video production. A lot of people think that they have nothing to say but in my travels across Canada I have seen and talked to many excellent orchid growers. The topic should be about orchids, anything about them would be fine. How you grow them, what is an orchid, possibly a short feature on your favorite orchid, etc., let your imagination be your guide. If you are interested in such a project, please let us know what the topic is and we will then work something out.
Just a reminder to all the orchid societies that receive this bulletin. Dues are now overdue!! If you haven't paid, please submit your $1 per member of your society today, as the due date was at the Congress in Calgary last April.
The latest word on CITES! As you know Cites is becoming more of a problem every time we turn around. There are now rumors that more orchid genera are being entertained for addition to appendix I. If this happens we will certainly be in a state of confusion. The group of people in Vancouver who are working on CITES will keep us informed as to what is happening and we will inform you if anything newsworthy breaks.
Until next time, Kenneth J. Girard.
Thank you everyone who sent back their club information updates. Almost everyone did and it was a great help. I've sent a copy of each to all the COC reps. PLEASE use them to correspond with each other about shows, speakers etc. -- the better we get to know each other, the better it gets!
Thank you to Claudio Rossi of SOOS for the excellent 'Trigger' article, I'm sure you'll all agree that it's most intriguing and will send us all back to the books in search of new triggers. IF YOU FIND ANY, OR KNOW OF SOME 'TRIGGERS' PLEASE SEND THEM IN AND I WILL PUBLISH THEM EACH ISSUE.
I am sending another inquiry to our COC reps to send me information regarding any Orchid Dealers in their part of the country - the results will be sent out as a directory with the next newsletter.
Oct 25-27 Frazer Valley Orchid Society, contact Robert Sutton
Nov 23-24 Niagara Region OS, contact Mario Ferrusi
Canadian Orchid Congress Fees
Society Membership $1.00 per society member
Individual Membership $15.00