Dendrobium devonianum, a challenge to grow and flower in the mountains of Puerto Rico

Years ago I brought this plant of Dendrobium devonianum after seeing a stunning photo of a flower in the Orchid Source forum.   As it often happens to orchid growers, the beauty of the flower overwhelmed any apprehension on whether the plant would grow under my climatic conditions.   In 2008 I acquired two small plants.  Both were just a few inches long and their roots were wrapped in coconut fiber.

The larger plant grew vigorously, when it bloomed I was very disappointed to find that it was actually Dendrobium aduncum.  The little plant grew slowly and produced comparatively weak growths.    The thin, wiry canes that it had didn’t give me too much confidence in its survival.  I was so concerned at the thinness of the cane that I measured the stem near the base of the plant and found that it barely was .8 millimeter wide.

Eventually, in 2011 the orchid produced a cane that seemed large enough to bloom.  But no flowers were produced.  Five years after it had arrived at my garden, in 2012 the orchid finally bloomed. It produced two short lived, pale flowers.  I was happy that it bloomed but sad that the flowers lasted just a few days.  The plant didn’t bloom in 2013.  In 2014 it has produced five flowers, its best performance yet. 

This orchid has proven to be challenging to keep in good shape in my garden.  It has lost canes for no clear reason.  I grows slowly compared with my other pendent Dendrobium.  Its leaves are short lived which means only the last foot or so of the growing cane is leafy at any given moment.  

In a location with a more temperate climate this orchid would do much better.  Given its spectacular flowers, and the fact that there are many growers in the northern countries which can give it the moderate temperatures it likes, I am surprised that this Dendrobium is not more popular.  The Bakers in the book on Dendrobium report that growers say this plant is difficult to grow, something that my own experience confirms. Most of the plants I have seen in captivity outside its native haunts don’t seem to be in a much better condition or more floriferous than mine.

In my experience this plant is not for the novice or neglectful grower perhaps unless you happen to live in those parts of Asia where this plant is native.   Even with the best care this plant may prove a disappointment if you live in an area where the local temperatures are uniformly high for most of the year. 

The plant is potted in a six inch wide wire basket.  It is potted in bark. It gets watered every three to four days.  It gets fertilized once a week during growing season and not at all between December and June.  It gets full morning sun but after 10:00 am it gets light filtered through the canopy of trees and palms.  It has never been repoted.  In my garden it blooms in May and June.

Dendrobium harveyanum is ready for its close up.

The flowers of this Dendrobium are a bit over 1.25 inches/3 centimeters wide.  The fringed petals are a salient characteristic of this species.  This is a miniature, the tallest cane of any of my plants is just 7 inches/18 cm tall.

Dendrobium harveyanum Rchb f. 1883, after seven years it is still doing well

 
(I wrote an article about this species in 2011, here I revisit some of my old observations and add a few new ones)

This orchid comes from Burma, Thailand, Vietnam, and the Yunnan province in China.  In spite of its large area of distribution it is rare in the wild.¹   Since its discovery in 1883, this plant was always rare, and for a long time it was totally lost to cultivation.²   Plants of this species were discovered in northern Thailand and then reentered cultivation.²   Unfortunately, even after it was rediscovered, this plant remained generally unavailable for many years, one could only enjoy its beauty in the occasional photo in a book or an orchid magazine.

When I first saw the flowers this orchid in a book, I was immediately captivated by their unique characteristics.  That was in 1990, back then I could find no source of these orchids in the United States.  I know this sound quaint in the age of the Internet, but back then you had to peruse through orchid magazines, select those vendors that might have the orchid, write a letter asking for a checklist, and then wait for weeks or months to see if you would get an answer.

In 2006 I finally found a source and was able to buy three plants.  Unsure how they would adapt to the local conditions, I mounted one on a branch and potted the other two in wire baskets.  The plant in the branch did poorly and even thought it bloomed, it did so weakly and eventually died.  It died even after I had removed it from the branch and planted it in a basket like the other two plants.

The two plants in the baskets did well and two years later bloomed.  They have bloomed unfailingly every year, sometimes several times in the year, since that time.  The two plants have responded in slightly different ways to basket culture.  One of the plants has grown slowly and is still well within the confines of the basket, the other one was a vigorous grower and grew to the edges of the basket and has continued growing on its sides.  I have never repotted these plants as I suspect that damage to their root system would severely set them back.  As for their culture, I followed the advice to grow them like I grow my Dendrobium farmeri.³

As you can see, all plants responded in a different way to cultivation under my conditions.  One peculiarity is that the most vigorous plant produces keikis from time to time every time a cane loses its base to rot.  The other two never produced keikis.  These plants are unbothered by most pests in my area.  A single pest is capable of damaging them severely is snails.  When a new cane is growing snails have been known to attack the tender leaves.  This has resulted in the plants being set back and weakened.  The result was poor blooming in the cane that sustained the damage.  On rare occasions, canes that are growing have developed rot in the growing tip and died.  It is unclear what has caused this.

Considering how rare this plant has been in cultivation, it was a bit surprising that it has proven to grow well with little special treatment.  It can withstand the local dry season with ease, with no watering, even when a whole month goes without raining.   Outside of its growing season I give it no fertilizing.

The two plants produce inflorescences at any time between late April and July.  Different canes of the same plant can bloom all together or at different times in the same year.  My plants have produced inflorescences with as little as two flowers and as many as thirteen.  I thought the flowers were slightly fragrant until one occasion when I brought a plant in the house.  In late morning I found that the flowers had become powerfully fragrant, much more fragrant than I had ever noticed.   Next time this orchid blooms I shall see if this was a onetime event or whether it always happens but I had never noticed.  Flowers can vary slightly in color and size of the lip but I have not checked if this a characteristic that varies between the different plant or the different bloomings.

One thing I have noted is that my plants have remained relatively small, with canes that rarely grow over six inches tall.   I have seen photos in the Internet of plants that seem to have canes taller than seven inches, but this has not been my experience.  Only once has my plant produced a cane larger than seven inches, a cane that was produced in the 2013 growing season and that topped its growth at eight inches (20 centimeters).  The size of the mature canes of this plant has been cited as being between 6 and 9 inches (17 and 23 cm)¹ and five and eight (15 and 20 cm).³

Given the relatively small adult size of this plant, it often is overlooked when visitors come to my garden and are greeted by Grammatophyllum and Vandachnis that literally tower over all other plants.  But when they are in bloom, the unique, canary yellow flowers of this orchid are truly eye catching.   In my experience this is a plant that is well worth growing. 

 

¹Baker, Margaret L. 1996. Orchid Species Culture.  Dendrobium.  Margaret L. Baker and Charles O. Baker.

²Menzies, David. 1991. Orchids.

³Schelpe, S., Steward, J.  1990 Dendrobium an introduction to the species in cultivation.

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.  

Rhychodendrum Cabalgata en Verde

This orchid is a cross of Rhyncholaelia digbyiana  and Epidendrum ciliare.  Both species have notable fringed lips.   Epi. ciliare has green sepals and petals and a relatively narrow lip that is white with fringed side lobes and has a long central projection.  Rhyncholaelia dygiana generally has green sepals and petals and a wide, deeply fringed green lip.  The Epi. ciliare parent of this cross is a particularly fine representative of the species, its flower has the largest natural spead of any ciliare awarded under the AOS system and was awarded a FCC in 2011.  The Rhyncholaelia parent is the cultivar “Laura” AM/AOS.  When I saw this Rhychodendrum it had two inflorescences, one with two flowers and another with three.  The flower count is reduced from the number the Epidendrum parent produces because of the Rhycholaelia influence.  

The Epidendrum parent dominates the appearance of the flower of the cross.  The Rhycholaelia influence shows as a widening of the side lobes and of the projection of the lip that is a particular feature of the Epi. ciliare lip.  The plant form is similar to the Epidendrum parent.  Since I saw this plant early in the morning I could discern no fragrance, but since both species are known to produce fragrance at night, I would expect it to be fragrant after the onset of darkness.

I have learned that only a few plants of this cross survived to bloom.  I have been told that there are just two clones of this cross.  I was told the other clone has even wider flower segments and produces more flowers, I hope one day I will see it.  I have seen three Epi. ciliare crosses and in two the Epidendrum is dominant in the shape and size of the hybrid.  I the third, a cross with Blc. Toshie Aoki, the flower is much larger than ciliare but from the appearance of the flower you would have a hard time guessing that the other parent..