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.

Myrmetonia ( Schombonia ) Summertime (Myrmecophila tibicinis x Broughtonia sanguinea)

I saw this orchid at the 2016 Puerto Rico Orchid Society show.  The plant is large, the flowers are produced at the end of long inflorescences that however are not as long as those of the Myr. tibicinis parent.  

Myrmecophyla tibicinis, cultural notes

In a basket, under the shade of a large avocado tree

Growing on a palm trunk in full sun

St. Croix Botanical Gardens

In areas with warm weather Myrmecophyla tibicinis does very well when grown in a basket or mounted on a tree.   This orchid can grow in full sun, in fact it needs a certain amount of full sun exposure or it will not bloom.  Keeping this plant in too much shade is a common error among beginners.  However, this plant seem to grow better when is given a slight bit of shade from the sun when it is at its most intense, which locally is between the hours of 11 am and 4 pm.

This orchid can produce a huge specimen plant if well cared for.  In one of the photos above you can see a truly humongous specimen in a Ceiba pentandra tree in the St. Croix botanical gardens.   To me the key to have a large and floriferous plant, aside from the right level of sun exposure, is giving it the proper fertilizing when it is producing new pseudobulbs.  This plant should be given a high nitrogen fertilizer when it is growing to help it produce full sized pseudobulbs.  Small, undersized pseudobulbs will not bloom.

The plant growing mounted in a palm trunk, in full sun all day long, produces relatively short inflorescences.  The plant in the basket, which is growing under an avocado tree with a comparatively open canopy, produces the typical long inflorescences.  The inflorescences grow until they emerge from the canopy of the avocado tree, then they produce the flowers.

Myrmecophila tibicinis [Bateman] Rolfe 1917

These flowers are from an enormous plant grown under a tree in Moca, Puerto Rico.

Schombocattleya Louise Fuchs, Schomburgkia tibicinis x Cattleya bicolor

This plant has given me some difficulty in its culture.  I have two of them, one seems to be all too prone to lose pseudobulbs to rot, the other is spotlessly healthy.  The one that is in bad shapeand gets lots of sun blooms realiably even though it receives next to no care and has small pseudobulbs, the one kept under more shade and which receives much better care doesn't bloom.  I have seen a large plant of this hybrid in bloom with a large inflorescence and it is a show stopper.  I will move the non blooming plant to brighter light to see if that is what it needs to bloom.  The color of the flowers in real life is darker than how they appear in the photos.   This plant is capable of producing up to six flowers.

Myrmecophila grandiflora (formerly Schomburgkia tibicinis var. grandiflora)

A full plant view that shows the six feet plus inflorescence.

The flower against the morning sky, note the ants in the bud.

A top view of the lip showing the exposed column that is said to be an identification mark for grandiflora

This plant was given to me a few years ago by a friend.  My friend had his plant growing on a citrus tree.  His plant was enormous, with many side branches, and had colonized a large area on the trunk of the tree.  She cut a piece with two pseudobulbs and gave it to me.  I was not sure how to pot this plant as I had previously lost some Myrmecophilas to base rot.  So I just put the plant in an empty basket and stabilized it with a few large chunks of bark.  The orchid spent many months in that basket with no sign that it was either growing or declining.  Eventually it started producing a new growth.

The new growth was of a much smaller size than the original pseudobulbs, probably due to the fact that the originalpseudobulbs had a meager amount of roots.  But as the pseudobulb matured it started producing roots.  The next pseudobulb it produced was slightly bigger, not much of an improvement on the first one.  However the plant started producing roots with increased vigor and the basket became filled with the plant’s roots.  It produced its first full sized pseudobulb on the third year on my possession.  Learned that it grew pretty fast once it got going and that it was crucial for getting a good sized pseudobulb that you provided abundant water and fertilizer during the plant growth phase.

When it first bloomed the inflorescence was damaged by some insect that kept nibbling on the stem of the inflorescence.  It produced only a few flowers.  The second time it bloomed the inflorescence was severely damaged and the plant aborted it.  The photos you see in this essay come from the orchids first and third blooming.

The flowers last from a week to ten days.  I suspect they would last more if I kept them away from the wind and pollinating insects.  The flowers open well during the morning but tend to collapse in a heap before midday.  To get good photos of the plant I had to get up early in the morning when the flowers were at its best.  The inflorescence shown in the photo topped out at six feet and six inches.  At one time it became entangled in the shadehouse roof wire netting, that is why the inflorescence has a slight bet to It.  The inflorescence got bent 90 degrees but to my surprise, once it was free of the wire, it slowly righted itself and kept on growing as if nothing had happened.

My plant is grown under shadecloth but the shadecloth allows quite a bit of light to come through.  I water it twice weekly when it is producing pseudobulbs and fertilize it weekly.  Outside of the time when it is growing it only gets water when it rains and it is not fertilized.  Ants love this plant and it is rare to see the plant without ants on it.  However the only ants I have seen in large numbers in this plant are black and don’t bite when disturbed, they just scatter in a panic.  My Myrmecophila humboltii, however, is guarded by a truly vicious type of large yellow ant that has a memorably painful bite.

This plant is fairly common in orchid collections in Puerto Rico and even people that don’t know about orchids sometimes have it in their gardens as a curiosity.  The fact that this plant, if planted in a favorable spot, can grow, and even thrive, with relatively little care helps it survive even in the hands of those that give their plants little or no care.

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.