Thursday, June 7, 2012

The stunning Dendrobium devonianum

A few years back I saw a photo of a flower of Dendrobium devonianum that was so spectacular that it took my breath away.  The photo was by Dale Borders and it was posted in the Orchid Source Forum.  I wondered if I could grow it since by all indications this was a high elevation plant whose range encompassed areas with more temperate weather than PR.  I asked Dale how he cultivated this plant and he told me that he grew it next to its Dendrobium primulinum.   Since I had a few years of experience growing and blooming Den. primulinum I decided to try this plant.
When I brought my first two plants of Dendrobium devonianum, back in 2008, I must confess I was underwhelmed by the sight of the plants.  The larger plant seemed scrawny, I had expected that, but the smaller one with its larger cane barely six inches long, was so unimpressive I thought it might not survive the process of becoming acclimatized to my local climatic conditions.  Eventually both plants started producing new growths, the larger one with vigor, and the smaller one at such a slow pace that it was glacial in comparison with the first one.  This pattern repeated itself every year, the larger plant growing ever faster and the smaller one barely making progress.  In 2010 I was quite excited to see buds on the larger plant, alas I was utterly disappointed when the larger one produced flower buds and it became clear it was Dendrobium aduncum.   To my defense I have to say that Dendrobium devonianum is an exceedingly rare plant in Puerto Rico and I had never seen one so could not tell it from Den. aduncum on sight.
The smaller plant kept growing exasperatingly slow and producing absurdly wiry stems.  The incredible thinness of the stem near the base is almost unbelievable.  The cane produced in 2010 was eight inches long but the width near the base was .8 millimeter.  Yes that is no typo, I actually used a caliper to measure it, the stem was less than a millimeter wide!  Even the 2011 cane, which is the one that bloomed measured three feet eight inches long but was a tiny fraction of an inch wide near the base of the cane.  To put it in metrics, the cane near the base is 1.2 millimeters wide, the cane is 1.17 meters long, around a thousand times bigger.  I want to clarify that the very thin part is only a short stretch near the base of the plant,  the rest of the cane is thicker, a little less than half a centimeter thick.
In 2011, to my surprise the plant started producing a new cane with previously unknown vigor.  The cane kept getting bigger and bigger unlike previous ones that would stop at a few inches after lackluster growth.  The cane eventually measured, as noted previously more than three feet long, which was five times bigger than the size of the previous cane.  Eventually the cane lost all its leaves and all I had to do was wait for the blooming season to come around.  And I waited, and waited and waited.  By the start of May all my other deciduous Dendrobium had bloomed, I assumed that the plant would not bloom.  One day in the first week of March, as I was watering the plants, I noticed that there were some slight swellings in the side of the cane.  By then the local rainy season had started and I wondered if it was really going to bloom or that it was going to produced keikis. 
The next few weeks were depressing. The plant kept producing flower buds and they would start to develop but after a while they would turn pink and fall from the flower.  This happened seven times.  I despaired of ever getting to see the flowers.  The fact that this is a Himalayan Dendrobium and at the time the plant was producing the buds the temperatures were sweltering and humidity sky high.
The last two buds managed to develop all the way to maturity and opened on May 5.  They are so beautiful that all frustration was forgotten.  I expect that as the plant develops larger canes and an even more extensive root system it will be able to bloom better.  The new growth is already nine inches long and it is slightly huskier than the preceding ones, the quoted size for the cane of this species is three feet long, but I expect this plant to exceed this size in the 2012 cane.
This is not a species for a beginner, particularly in Puerto Rico.  It demands patience and consistent care.  I grow this species at an altitude of 1000 feet in the interior of PR, I don’t know how it will fare in the coastal lowlands which in summer can reach high temperatures in the nineties degrees range.