Monday, March 28, 2011

Dendrobium farmeri, a small Dendrobium that can produce an impressive show


The white form of the species, albiflorum
The most common form in the wild

A very light pastel pink form

A highly colored type with smaller slightly cupped flowers

A pink form, the orange lip is due to the fact that they were photographed with flash
Two slightly different forms side by side, note the long slits for aireation on the pots

The albiflorum form next to a pink one

A plant almost totally covered with flowers

This deeply colored form even has a purple dot in the lip
Dendrobium farmeri is an orchid that has a geographical distribution that goes from the eastern Himalayas to Malaysia.  This means that plants of this species can grow in environmental conditions that range from fairly cool to sweltering hot.  But this doesn’t mean that all plants of this species will grow under any condition that you can expose them.   There are local populations of this species that have adapted to certain regimes and will not bloom in the environmental conditions don’t match their seasonal needs.  Visitors to their natural habitat remark that the plants are often seen growing in trees near river courses.  I have had the experience of growing several different plants of Den, farmer, I will detail my experiences in the following paragraphs.

A few years ago a friend gave me as a gift a very peculiar farmeri plant.  It had a long and thin stem that about halfway of the way up the stem would fatten to a ridiculously disproportionate girth.  It was the tallest farmeri that I ever seen with canes 30cm long.  My friend gave me the plant because it would not bloom for him (he lives in the coastal lowlands of Puerto Rico), at that time the canes were about 15 cm tall.  What made them grow to 30 cm was the heavy application of water and fertilizer during its active growth phase.  After two years under my cultural regime the plant produced the two largest inflorescences that I have ever seeing in a farmeri plant.  I have wondered this plant was palpebrae but it lip didn’t show the fringe that palpebrae flowers are said to have.  This plant sadly died unexpectedly of a stem rot that had never previously attacked any farmeri plant in my collection and has never attacked one since this one died.  This plant was cultivated in a plastic basket that it eventually filled with roots, the only potting material were several large pieces of bark.  The flowers of this orchid were pure white with a bright yellow coloration in the lip.   This orchid was a large sized representative of the albiflorum variety.  All my other plants are smaller than this one and don’t show the shape of the stem this plant had.  I suspect this plant came from and mountainous region and needed a sharp drop in temperature to stimulate blooming.

I have several smaller (less that 20 cm tall) slender types will bloom equally well in the mountains as in the coasts of Puerto Rico.  In the early nineties there was a huge importation of Den. farmeri, the plants were sold at the Puerto Rico Orchid society show in San Juan.  When these plants bloomed they all turned out to be the white variant of the species Den. farmeri albiflorum.  For many years var. albiflorum was the only one that was seen in orchid exhibits in the island.  During the course of the nineties I saw exhibited some impressive specimens and I personally had a plant that would produce more than a dozen inflorescences at the same time.  Unfortunately many plants of this importation showed cupped, nodding flowers, this detracted from the beauty of the blooms.  It is not clear whether this cupping of the flowers is due to genetic or cultural causes.   

A few years ago there was another importation, this one consisted almost entirely of the pink form of the species.  I saw one plant in bloom and was so smitten with it that spent $60 dollars. That is right I spent almost five times the value of a seedling of this type of orchid in a single plant.   But I loved the purplish color of the flowers and was quite happy with my purchase.  In due time the flowers fell (the flowers of this plant last from a week to ten days, less time if weather is really hot).  In about two week the plant bloomed again and to my surprise the flowers were different!   In this blooming the flowers were pink, larger and fuller than in the firsts bloom.  A few weeks later the plant produced a single inflorescence which was again different from the previous two.   In this case the flowers had a very delicate pastel pink color.   After careful examination of the plant I had to conclude that I actually had three plants growing very close together in a single pot.

With extreme care I disentangled the three different clones and potted them separately.  Two of them have been growing well with no problems, the third one almost died.  Why?  Because under my conditions farmeri seems to be extremely vulnerable to rot after it has been repotted.  The plants can live for a long time, a decade or more filling and growing over their old pot in great health.  But every time I have divided and repotted the plants I have lost many of the pieces.

My saddest experience was when I took out of its pot a specimen plant of the variety albiflorum that had been in the same basket of about ten years.  I took the plant out of the basket divided it in several pieces and potted each piece separately.  After a few days they started dying, at the end only a tiny two cane piece survived.  This piece has been growing painfully slowly but at least is alive and has started producing small but pleasing inflorescences.  So what is my advice on potting this plant?  Put it into a basket that will allow the plant to grow for years without the need to repot.  Use the hardest most decay resistant media you can find, don’t use cheap bark and for Peter’s sake don’t even consider the super cheap landscaping bark for this orchid. 

The most vexing problem I have had to deal with this species is the proclivity of some clones to produce new canes lower in the stem than the original cane.  As a result of this habit the new canes end up growing through the media and sometimes into the media before growing upwards.  These types may be better grown in slat baskets or mounted on tree fern slabs.

For most of the year I don’t fertilize this orchid, I only fertilize when the plant is producing new growths.  When this plant is growing the canes grow comparatively fast so you need to give it fertilizer frequently.  When my plants I growing I give them diluted fertilizer at every watering.  I use whatever fertilizer I have on had, be it 20-20-20 or any other combination, I have never seen any difference in growth as long as I fertilize the plant regularly.

My plants bloom in February, March and April.  The albiflorum type produces a single flush of inflorescences that open all at the same time.  The pink flowered types bloom once a year when they have few canes, but once they grow large they bloom twice, once in February and again in March or April.  My main problem has been that the flowers are wildly attractive to thrips which will attack them in great numbers even when they have been rendered toxic by the application of pesticides.  To avoid having the flowers damaged with these hateful pesky pests I move the plants indoor for the duration of the blooming period.  As the plants mature and gain size they can produce very impressive flowerings.

These plants need bright light to bloom well.  I grow my plants in a terrace where they get full morning sun for two to three hours and then sunlight filtered through the trees the rest of the day.  Too much shade results in poor blooming or even no blooming at all.
When my plants are growing I water them almost daily to sustain the rapid growth of the canes.  During the summer my plants get a daily soaking from the thunderstorms that form over the mountains every day.  The plants take the wetness with little complaint.  When the dry season starts in December I stop watering the plants and allow them to dry, but not so much the canes shrivel and twist, if the canes start to get too wrinkled I water the plant lightly.
This plant is an excellent addition for an orchid collection if you can fulfill its relatively modest needs.

2 comments:

Gabriel said...

¡Simplemente hermosas! Esto de las orquídeas me está gustando cada ves más.

Raquel Terga Flasco said...

Can I send you a picture of my orchid for your opinion? I received it as a gift 2 years ago (in February) and then it bloomed again 2 or 3 months later. It has not bloomed again.