Myrmecophila culture: Why my plant won't bloom? A checklist of possible causes

The most common question I get asked about Myrmecophila orchids is “why won’t my plant bloom?” I have decided to make a checklist of the reasons Myrmecophila might not bloom. This will help guide you to find the way to make your plants bloom. 

1. Is the plant adult sized? Myrmecophilas are plants that in the wild live in a symbiotic relationship with ants that live inside their hollow pseudobulbs. These ants fertilize the plant with their feces. Plants in cultivation that don’t have ant colonies might become stunted and never reach adult size. So the first thing is to get an ID the plant and check on the size of an adult pseudobulb. If the pseudobulbs are smaller than the reported size for the species they you need to make sure you fertilize this plant with a high nitrogen fertilizer and give it plenty of water when it is producing new pseudobulbs. 

 

2. Is it getting enough sunlight? Myrmecophilas are not plants that bloom in shady spots. They will grow well, and might eventually produce a large clump of pseudobulbs. But they will not bloom. If a plant is an adult and is not blooming, the next thing to check it if it is getting the level of light it needs. I have seen Myrmecophilas growing quite well in places where they get full sun for most of the day. Personally, I put my plants close to the shade cloth, I grow them under a shade cloth that allows most of sunlight to come through. The best plants I have seen were grown with full exposure morning or afternoon sun, but protected from the midday sun by shade cloth or the canopy of a tree. 

 3. Is it in the proper location for blooming? Myrmecophilas are often planted on trees with dense canopies. This keeps the plants in shade. They will grow well but not bloom. A friend had a massive plant of Myr humboltii growing in a citrus tree. It had never produced a single flower. A hurricane severely damaged the canopy of the tree, allowing full sunlight to reach the Myrmecophila. As a result, the plant bloomed. 

 4. Is it receiving the care it needs at the critical time in its growth cycle? Most people I know affix their Myrmecophilas to a tree and that is that. No watering, except for rain, or fertilizing, except what it gets naturally from the tree or from ants if they have colonized the plant. This is a hit or miss approach. Some plants will grow well and bloom, other will rarely bloom and some will never bloom. I have seen Myr humboltii and Myr exaltata growing on the stems of palm trees doing well and blooming. I have seen a massive plant of Myr humboltii under the thick canopy of an avocado tree, with no evidence of it ever blooming. You need to observe your plant, and when it is producing a new pseudobulb, give it the watering and fertilizing it needs. 

 5. Is it healthy? Some Myrmecophilas are attacked by a type of fungus that kills their stems and primordial buds. You can tell this because part of the stem that should be green look like cork. The sad thing about this is that often nothing can be done. The warning sign is often that the plant is not producing new growths. The fact that the rest of the plant can look good even if it has lost all its capacity to produce new growths, and can remain looking good for years, is a confounding thing. Plants like this will not bloom ever. On occasion an older side bud will produce healthy new growth. But if a plant has not produced new growths after a few years, it is probably a lost cause. 

 6. Is the plant getting the proper nutrition? Sometimes you can do all the above things and still a plant won’t bloom. Sometimes a few extra things can give it the push it needs to bloom. I have used a dilution of Epson salt to give the plants more access to magnesium, in particular those that are growing in full sun and look yellow. A fertilizer with a high nitrogen concentration is recommended when the plant is producing new growths.

Myrmecophila humboldtii [Rchb.f] Rolfe 1917, culture notes on growing this plant on the trunk of an avocado tree

When I first tried to grow Myrmecophila humboldtii, I tied it to an avocado tree.  Unfortunately, the place was too shady for the plant to bloom.  However it proved a very favorable place for it to grow.  And grow and grow and grow.  SInce it was not blooming it poured all its energy into producing canes and eventually became a large mass of pseudobulbs.  In time I removed pieces from this mass and moved them to sunnier spots where they bloomed.  The plant has continued growing up the tree.  The pseudobulbs shown in this photo have all died and decayed, but there are plenty of them higher in the tree.  The pseudobulbs are hollow and are inhabited by some ill tempered yellow ants.  The ants come out only at night.  If you damage the pseudobulbs they will come out.  The sting of these ants is painful and might produce some swelling.  For more information on the culture of this species, you can read: http://ricardogupi.blogspot.com/2011/01/myrmecophylla-schomburkia-humboltii-ant.html

Myrmecophyla (Schomburkgkia) grandiflora, an ant orchid from Central America

Head on view of a flower

The top view shows the ruffles of the flower segments

The flowers partly close at night

Note that the inflorescence has sustained some damage from insects feeding just under the scar of the first flower.  You can also see the sequential mode of flower production

A flower over a slab of limestone to show the color of the flower under sunlight

Myrmecophyla grandiflora, has a geographical distribution that ranges from Mexico to Colombia.  It inhabits dry areas where it grows both on trees and on rock.  The pseudobulbs of this species are hollow and it is said that in the wild there are always ant colonies inhabiting them.  It is reported that the pseudobulbs of this plant can reach up to 18 inches long and have two to five short coriaceous leaves on top.

A few years ago I was given a rootless three pseudobulb division.  I planted it in a custom made basket with no media (I was afraid that the plant would be attacked by an insidious disease but more on this below).  I tied the plant to the basket and watered and fertilized it like I do the Cattleya in my collection.  In due time the plant produced a new growth, after that it engaged in the copious production of roots, it repeats this cycle every year one or two times.  The plant did well in the basket but in due time it became clear that it would never reach its full potential with no media from which to draw moisture and fertilizer.  I then added some large, hard chucks of bark to its media, which the plant eventually enveloped with its roots.  However since it had started as a completely rootless division it took several years to achieve enough strength and size to bloom.

My plant produces two growths a year and sometimes tries to bloom from both of them.  Unfortunately the inflorescences of this orchid seem to be attractive in the extreme for some gnawing insects and I have lost a few to them.  Now I routinely give a slight dusting to my plant with some insecticidal dust to prevent any such critter from destroying them.  Given that these plants are hung on the shade house from wires about four feet long and the inflorescences are sometimes four feet long, the critters that eat them seem to be so highly motivated as to travel all this distance to munch on the tender inflorescence tip.  But use any insecticide with extreme care, and follow all instructions to the letter.  I, in particular have to be very careful as my shadehouse if full of fish tanks that could become contaminated with insecticide which would kill my beloved fish.

The flowers open widely in the morning but become floppy during the hottest hours of the day.  I am not sure if this happens everywhere but it is what happens in my garden.  The same thing is done by the flowers of Myrmecophila humboldtii in my garden.  The inflorescence keeps elongating and producing flowers for a few weeks.

I have found this plant to be generally problem free and a vigorous grower that can grow into a hernia inducing specimen plant.  The very long inflorescences can be an annoyance, as the flowers can end up so high up that you practically have to put the plant on the ground to enjoy them.  This plant responds well to constant watering and weekly fertilizer during its growing phase.  My plant produces very closely spaced pseudobulbs which mean I have to watch carefully when the new growth is forming so that it won’t get trapped in the media or the wire of the basket.

My plant is not growing in full sun, I have it under shade cloth, but one that allows a high percentage of the sunshine to pass through.  The sun in my location can be quite harsh on orchids, especially during the dry season, so I almost always give my plants some sort of protection from the sun during the hours surrounding noon and early afternoon.  Other Myrmecophyla that I have grown in full sun during the whole day have responded by becoming stunted.

This orchid seems indifferent to the local level of humidity although during the height of the dry season the pseudobulbs can become furrowed from water loss.  It gets watered once every week year round, along with whatever it gets from local rainfall.

I have always admired this plant but for many years I was hesitant to include it in my collection.  The reason was that I found that in my garden lurked a specially evil and insidious disease to which these plants were particularly vulnerable.  What makes this disease (I am not sure if it’s a fungi or a bacteria) exceedingly vile is that it won’t kill the whole plant, only the buds capable of new growth and a tiny area around them.  As a result of this damage the plant won’t grow or flower, but since everything else is ok, it still looks like it is in great shape.  I discovered this disease when my plants of Myrmecophila exaltata and a plant of Myrmecophila humboldtii would not grow or bloom for several years in a row.  I think I have found the way to stop or limit the damage this disease can inflict on my Myrmecophila.  I observed that all the plants that got this disease were planted in fairly water retentive media that was in contact with the stems on which the pseudobulbs sit.  By planting my orchids in fairly chunky media and keeping the base of the pseudobulbs a fraction of an inch over the media the disease seems to have been controlled.  So far tibicinis has not been molested by this dreadful disease.

Of all the Myrmecophyla orchids formerly known as Schomburgkia this is probably the one that is under the wider cultivation.   There is hardly any serious local orchid grower that doesn’t have at least one plant of this species.  There are also a number of hybrids of various sizes and colors that occasionally make their appearance at orchid shows but they don’t enjoy a fraction of the popularity of the Myrmecophila parent.  I have seen plants of this species of all sizes in the collections of various orchidists which makes me think that there is some variation on the plants available locally.  But all the flowers I have been able to examine were pretty similar regardless of the size of the plant that produced them.

In conclusion,if its minimum requirements of temperature and watering are met, this plant can survive almost every vicissitude that ordinarily sends other orchids to that great pot in the sky.   I have seen them growing equally vigorously in the hands of skilled growers as well as those of rank amateurs.

If you have any question just leave it in the comment section under the article.

Myrmecophyla (Schomburgkia) humboldtii an ant orchid from Venezuela

A fully expanded mature flower

A paniculate inflorescence

Note that several of the flowers are partly closed, this is normal

A plant on a wire after one year of growth

The same plant as before but after three years of growing hanging from a wire

Roots are produced in a single massive burst

An ant patrolling the plant, the pseudobulbs are hollow and house ant colonies

When I was given this plant as a gift, many years ago, I had little information on its blooming habits, growth patterns and cultural needs.  In those ancient “pre-Internet” times finding information about an obscure species of orchid meant going to a university library and hoping they had a book about orchids that would give you some guidance.  Unfortunately even when you found some information about your plant often the information was in the form of a taxonomic description with no details of its cultural needs.

As a result of this lack of cultural information this orchid remained a mystery to me. The issue was that growing this plant proved easier than pie, however getting it to bloom seemed an impossible dream.  So year after year my plant would grow into an ever expanding gargantuan specimen plant with no blooming ever.  Eventually the Internet entered my life and through places like The Orchid Source forum I began to exchange information with people that actually grew this plant in its natural habitat in Aruba.  Myrmecophylla (Schomburgkia) humboltii is native of Venezuela and can also be found in the Netherland Antilles.  

Then I found that I had misunderstood what this plant needed to bloom and was growing it too shady.  It needs full sun to bloom but it also needs to produce large and strong pseudobulbs.  Also I found that the roots and the inflorescence are extremely vulnerable to insects and snails which will travel long distances to attack the tender parts of the orchid as they are growing.

To get the best out of this plant you need to give it particularly careful attention when it is in the growing part of its seasonal cycle and when it is producing roots.  Full sun has to be accompanied with frequent applications of fertilizer and abundant watering.  If these are neglected during this plant growing phase the pseudobulbs will be small and most probably will abort their inflorescences if they even try to produce them.  Medium sized pseudobulbs will produce racemose inflorescences that will have a few flowers open at the same time.  But if you manage to get this plant to produce the largest pseudobulbs possible the inflorescence will become paniculate with several flower bearing branches.

I have discovered that under my conditions potting this plant is not a good strategy.  It grows well and flowers acceptably when growing on a dead tree where it gets abundant sun.  But my best growing plants and the ones that bloom best are growing hanging from wires with no material or slab to grow on.  I have no idea why this is so, it seems counter intuitive but there is no denying that the ones growing completely in the air do better under my climatic conditions.

My plants bloom between winter and spring if the inflorescences manage to develop without being damaged.  It has been my sad experience that the inflorescences of this plant in particular seem to be an irresistible treat to insects, millipedes and snails.  Even hanging the plant high doesn’t deter the pests from attacking the tender inflorescences.  So when I see an inflorescence start to develop I give the plant a light dusting of an insecticidal dust.  It has been darkly satisfying to find the dead insects that strived to make a savory dish from the inflorescences.  Since there are many fish tanks around where I grow the orchids I use insecticides with extreme caution and precision and follow the label indications to the letter.

The flowers of this orchid are lovely and among the most full of the genus.  But someone visiting the garden around the hottest hours of the day could be excused if he/she found the flowers disappointing.  The reason is that the flowers are at their best in the early morning and when the day turns hot they turn floppy and partially collapse, only to perk up the next day.  Because the inflorescence produces just a few flowers at a time this plant can be blooming for a few weeks as the inflorescence elongates.  The flowers of this orchid continue expanding in size for the life of the bloom and achieve their largest size just before collapsing.

This plant is highly esteemed in horticulture and due to its ease of culture it is fairly common among local orchid collections.  A an often heard complaint is that it is shy blooming but this comes from growers that keep their plant under shadier conditions than those conductive to blooming or that have undersized plants due to lack of proper fertilization and watering during their growing season.  There is a rare white flowered variant of this species but I have yet to see a plant in bloom of this variety even though I know of people that have grown it successfully.

This orchid has hollow pseudobuls which are colonixed by ants. My plants host several species of ants but usually the one that is most conspicuous is a yellow one with a particularly nasty sting.  Unfortunately the presence of the ants doesn’t seem to deter the pests.