Dendrobium culture: No, its not dead.

For most orchid growers nowadays, Phalaenopsis are the gateway drug to bigger and more expensive plants.  But the Phalaenopsis that are now widely available are the product of many decades of hybridizing toward producing a plant that will survive in the average home even when (shudder of horror), watered with ice cubes.   Orchids species are an entirely different beast.  With 30,000 species (at least) species orchids show growing patterns and seasonal cycles very different from your average hardware store Phalaenopsis.   That is why it is important to read about the plants you buy.  A lot of orchid growers do impulse buying and then are bewildered by the way their plants react. 

 An example of a plant that can confuse a novice grower that is trying species is Dendrobium devonianum.  It produces slim canes that can be almost a meter long.  Unlike the leaves of Phalaenopsis, the leaves of Den. devonianum are slim, delicate and are soon deciduous.   During the growing season a cane of this species has leaves near the growing end of the cane with the rest quite bare.   When the cane stops growing, it eventually sheds all its leaves and for months afterwards it looks like its dead.    If the canes have been exposed to strong light and have developed a purplish color, they can look even worse.

This is an adaptation to the cold dry season when the trees lose their leaves and it rains little.  The orchids then have to endure months of drought and harsh sunlight.   My plant blooms in April, just before the local rainy season starts.  For months it looks like a mass of dead and shriveled stems.   But this is deceptive.  In the nodes of those leafless stems the flower buds are maturing.  A well flowered plant is quite impressive.

If you look at the top photo, the orchid looks like its in a wretched condition, ready to be thrown into the trash can.   But if you look closely, you can see the remains of many inflorescences in the second longest cane.   Note the very small root ball.  That is not unusual, if a plant is well fed and watered it will produce just the minimum of roots it needs to fill its needs.   In the bottom photo you can see the cane covered with flowers.

Dendrobium devonianum Paxton 1840

 I brought this Dendrobium last year.  One of the few orchids I have brought after hurricane Maria.   This plant has been delicate and lost two canes to rot during the rainy season.   However the youngest cane survived.  The cane is just a fraction of the size of the older ones it had when it arrived, but to my surprise it produced flowers.  Not many but I don't complain.   I have read Dendrobium devonianum is quite variable but I was puzzled when the flowers started opening.  To me it seems as if someone grafted the huge lip of Den, primulinum of a devonianum flower.  I have never before seen a Den, devonianum with such huge yellow dot and without purple on the distal tip of the lip.   Hopefully, next year the plant will be larger and stronger and will produce even more of this beautiful flowers.   The flowers are strongly fragrant in the afternoon.

Dendrobium devonianum Paxton 1840

My plant has bloomed again.  Only with three flowers, but considering this is a plant from a temperate climate, I am happy it blooms at all.  It is challenging to grow and loses vigor and size if it doesn't get consistent care.

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.