Dendrobium harveyanum Rchb.f. 1883, blooming late in the year, months out of its normal blooming date.

Hurricane Maria caused grievous damage to the forest where I live.  Many trees fell and the canopy was destroyed in most of the forest.  Humidity and rainfall dropped.  Because there was no canopy the area temperature went up.  Also without the canopy the full power of the tropical sun hit all the understory plants burning them severely and killing some.  I lost many of my orchids to the changed environmental circumstances.  But some survived through it all.  Among them Dendrobium harveyanum.  In the last month it has not rained and the plants are suffering.  I wonder if this period of low humidity triggered this out of season blooming of the harveyanum.

Dendrobium harveyanum Rchb.f. 1883 blooming in 2015

This orchid bloomed for the first time in my garden in 2008.  Since then it has bloomed every year without fail.  The only complaint I can make is that young plants can be slow to reach blooming size,  By the way, this is a miniature species, the largest cane this orchid has ever produced for me has been all of nine inches tall.  Canes that are six inches tall can bloom and on well established plants even smaller canes four to five inches tall can bloom.

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 in a handmade wire basket

When I got my plant of Dendrobium harveyanum it was a tiny seedling with canes barely two inches tall.  My main concern was that it would lose its roots to rot during the height of the rainy season, when it can rain every day for weeks or months.  On the other hand, during the dry season, not a drop falls from the sky for weeks and humidity can be low.  I decided to make a wire basket that would address the needs of the plant during both extremes of weather.   I made a wire basket four inches deep and four inches wide, for a miniature orchid, such as this Dendrobium, this is plenty of space to grow for years.  I filled the bottom two inches of the basket with bark,  then I put the plant on top of it.  The wire basket ensures that even at the wettest of the wet season the water drains away and the roots have access to oxygen.  In the driest part of the dry season I dunk the plant in water and the bark holds up just enough water to keep the orchid from shriveling too much.  This plant has been in this basket for eight years now and it seems it is good for at least two or three more.  When the canes reach the wall of the basket I will cut a hole in the basket to let the plant grow in the outside of the basket.  This plant has two inflorescences, one that is open and another on the way.  The tallest cane is seven inches tall, a pretty good size for this species.

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.

Dendrobium harveyanum, an orchid with canary yellow flowers and unique fringed petals

A freshly opened flower

Front and side view of the flowers

A fully expanded flower

An inflorescence with fully expanded flowers, the inflorescence is wet due to a hard rain 

A cute little species with unique flowers

                Dendrobium harveyanum Rchb. f. is a small statured species that produces canary yellow flowers with densely fringed petals.  The fringed petals are a salient characteristic of this species and make it unique in the Dendrobium group.  Many species have fringed, hairy lips, but with the exception of rare cultivars of Rhyncholaelia digbyana that have slightly fringed petals, no other species has petals like Den. harveyanum. 

                 When I first became aware of this species owning it seemed like an impossible, unrealizable dream.  It is found in the wild in Burma, Thailand, Vietnam and China and all sources agree that it is a rare in the wild.  Even in cultivation the plant didn’t seem to be plentiful and in those pre-Internet days even photos of it were not often seen.  But those few photos that I found convinced me that this species was well worth the effort of cultivating if it ever became available.

                In 2006 a US orchid vendor announced the availability of seedlings of this species and I promptly ordered three.  When I received the plants they had canes of two to three inches of height.  The height of mature canes of this plant is between six and nine inches to it could be said that even though the plants seemed small they were already well developed for their species.

                I planted the seedlings in wire baskets three inches wide by four inches deep.  The potting media was small sized bark.  Growing these plants in wire baskets ensured that the roots would get plenty of access to air.  Giving the roots access to oxygen a critical factor in the culture of many Dendrobium which tend to deteriorate and die in cultivation because they are intolerant of deeply packed and poorly ventilated media.

                The plants are grown outdoors in an open terrace that receives full sun for two or three hours between eight and eleven am.  After that it gets sunlight filtered through the trees.  New leaves in my plants display a pleasing wine coloring when they are developing probably in response to the high light levels of the early morning.

                Local temperatures fluctuate between 85 F and 75 F at the height of summer and 75 F to 65 F in the coldest part of winter.   For a few weeks in summer temperatures can go over 85 and even into the nineties. For a few weeks in winter temperatures can go under 65F but this plant doesn’t seem to be bothered in the least by either the hot or the cold end of the temperature spectrum.

                The plants were watered daily when they were producing new canes and fertilized with a high nitrogen fertilizer once a week.   When the canes were almost fully grown the applications of fertilizer are stopped.  No fertilizer is given when the plant is not producing new canes.  Local humidity varies with the seasons, it fluctuates between 40% and 90% during the day in the dry season but in the wet season it always stays over 70% and in particularly rainy parts of the wet season it can get close to a 100% nightly for many weeks.

                In Puerto Rico, which is in the tropics, we have a dry season that lasts from January to April.  During this time of the year I water the plants lightly once a week to mimic the effects of the rest period they would get in their native forests.  The canes of the plant become furrowed but otherwise the plants seem little affected by the decrease in watering frequency.  I start watering and fertilizing as soon as I notice new canes growing from the base of the previous year canes.

My experience growing this plant has been complex due to the different way the three plants I brought fared under my care.  The three plants were small seedlings when they I received them.  One of them started growing vigorously and quickly reached a height of six inches which is the maximum size they have attained under my care.  Another plant has produced canes of about four inches in height but no bigger.  One plant grew weakly became infected with a bacterial or fungus rot and almost died, it has remained small with canes about two inches tall.  All of the plants have bloomed, even the tiny one.  The only one that blooms every year is the tallest.

I know this orchid can reach sizes larger than those of my plants but there seem to be some local factor that is constraining their growth.  At the moment it is not clear what this factor is but my suspicion is that that the local conditions are a bit on the hot side for this species, and that it would fare better if it didn’t have to endure the high, into the nineties, temperatures of the local summer.

To my surprise one of my plants has produced keikis, something that is not often seen in this type of Dendrobium.  The keiki formed in a cane whose base rotted away.  They are growing quite well on bark and are treated the same way as the adult plants.  The tiny canes of the keikis are fat and short, not so similar to the adult cane.  In my other Dendrobium of a similar cane configuration I have never seen a single keiki even when every bud at the base of the cane has died.

This Dendrobium is a wondeful miniature that will amaze and delight friends and visitors with its beautiful and peculiar flowers.  The flowers are unfortunately short lived, they last a week at most under my conditions, and perhaps it’s the high local temperatures that shorten the lifespan of the flowers.  I advice protecting the flowers from rain as hard rain can give these fuzzy flowers a bad hair day and spoil somewhat their “hairdo”.  The flowers have a honey fragrance.

Sometimes when you see a plant labeled as “rare” you think it might be difficult to cultivate and reluctant to bloom, but in this case this has not been true.   Local insects have not bothered my plants and, with the exception of the rot that attacked the smaller plant and one of the old canes, the plants don’t seem to be too vulnerable to the local bacteria and fungus. 

Fragrant Dendrobium, ideal for a perfumed tropical garden



Dendrobium anosmum, all plant of this species I have grown are capable of producing the strong sweet fragrance characteristic of this species, the scientific name, anomum, which means without fragrance, must have been given by an anosmic individual!  This species when well bloomed can produce a powerful fragrance that can be clearly smell from many feet away.

 I have grown Dendrobium orchids for many years and it is one of my favorite orchid genera. Of the Dendrobium, the ones I like best are the fragrant species and hybrids. In the following article I will share details on the species and varieties I have grown, on their fragrances and on the particular quirks that the various species have exhibited under my culture.




Many years ago, in a book whose title I can’t remember, I read about a circular garden that was divided in six parts. Each part of the garden was devoted to a different sense. The garden had five wedges, where all the wedges converged in the center there was another circle, this one devoted to the sixth sense, intuition, and planted with only with golden flowers. This garden captured my imagination, but unfortunately I could not make one. My work as a wildlife biologist has meant that I have lived either in urban areas near universities or deep in protected forests, in these places this type of garden was impossible. But in these settings orchids allowed me to enjoy delightful fragrances, lovely colors and interesting shapes without the need of large spaces, digging, or modifying the landscape in any significant way. Orchids had also the virtue of portability, when I moved, (something that has happened several times during my career), I just took them with me with little problem.


Of all the orchids I have, the Dendrobium represent the best combination of ease of culture, resistance to pests and consistent flowering. This didn’t happen by chance, I did my homework and tried to acquire those species that were best suited for my climatic conditions. Getting the information on the cultural needs of the particular Dendrobium you want to grow is very important as some species need a certain degree of seasonal variation of temperature and moisture to stimulate the buds in the cane to change from the vegetative to flowering mode. Pest resistance is important to me as I don’t want to have to continually use pesticides just to keep my plants in good condition. I do use pesticides but on spot applications and not as preventive measures. In respect to consistent flowering, taking care to give the plants the proper culture they need goes a long way toward achieving regular flowering even on plants that are sometimes labeled as difficult. I suspect that some of the difficulties faced by growers getting their plants to bloom may have to do with growers trying to grow them under conditions that are not really suited to that particular species.

I grow my orchids outside, in a terrace and in a shade house. I live near the central mountain range of Puerto Rico at an altitude of 1000 feet (350 mts), near the center of the Rio Abajo State Forest, where I work. The local temperatures range from 60F (16C) at night at the peak of winter to 90F at daytime in the height of summer, daily temperature variation is about 10 to 15 degrees. There are just two seasons, a dry and a wet one. Humidity fluctuates most of the year between 70 and 80% but varies from 40% during the day at the peak of the dry season to close to 100% at night during the rainy season. The plants are watered weekly during if it doesn’t rain. The plants are regularly watered during the dry season with the exception of those that need a seasonal dry spell. The plants receive fertilizer only when they are growing. Some effort was made to find the optimal sun exposure for each species. It was found that most bloom much better with several hours of exposure to full sunlight in the morning.

Dendrobium anosmum alba, small flowered, small lipped clone

Dendrobium anosmun var. huttoni

The most common type of Den. anosmum is also the most floriferous, it is capable of producing more than sixty flowers on a single cane

Den. anomum variety from Thailand, the flower is suspiciously similar to Den. Nestor but the canes are unique and not similar at all to those of Nestor

Den. Nestor clone, favoring the anosmum parent, but note the fuzzy lip that betrays the parishii ancestry, at time sold as anosmum, all Nestor I have grown have the sweet fragrance associated with anosmum

A Den. Nestor that favors the parishii parent

A Den. Nestor that is quite distinct from most other forms hybrid

A very small lipped form of Den. Nestor with very thick textured flowers

In the front, Den. farmeri var. albiflorum, an outstading clone of this type, in the background a typically colored form. The fragrance is faint but clearly felt when there are many flowers

A flower of Den. farmeri albiflorum

Den. farmeri, a faint fragrance

Dendrobium harveyanum, formerly an extremerly difficult to find species, a slight honey fragrance

Den. crumenatum, powerfully fragrant at certain times of the day

Den. parishii, delightfully frangrant with a sweet note

Den. chrysotoxum, a sweet slight honey fragrance

Den. fimbriatum var. oculatum, a sour citrical fragrance

Den. nobile, a slight sweet fragrance

Dendrobium moschatum it has complex fragrance delightful to some, unpleasant to others

Dendrobium spectabile it has a complex fragrance sweet to some, to others like crushed stinkbugs