Growing Aerangis citrata
This is Aerangis citrata, a miniature orchid species, that’s endemic to Madagascar.
Aerangis citrata naming
The genus ‘Aerangis’ gets its name from the Greek words aer (air) and angos (vessel or container), as plants grow in the air (epiphytically) using aerial roots, and the flowers each feature a nectar filled spur. The second part of the name, (the specific epithet) ‘citrata’, refers to this orchid’s flowers, which are sometimes pale lemon in colour, when they first open. Louis-Marie Aubert du Petit-Thouars, who described the species in 1822, referred to the flowers being ‘jaune citron‘. My Aerangis citrata plants produce inflorescences that are creamy white as the flowers open; the blooms rapidly age to pure white.
The flower’s pollen cap is lemon yellow, on newly opened blooms. You’ll need to examine an individual bloom very closely, to see an Aerangis citrata flower’s pollen cap for yourself, as they’re very small. The yellow colour is most prominent on the caps of newly opened flowers. The vibrancy of Aerangis citrata flowers’ pollen cap fades rapidly, as the blooms age; swiftly changing from fresh lemon-yellow colour to a golden-brownish toned hue. It’s a quick transition and a subtle detail to spot on a miniature sized plant, so it’s easy to miss the pollen cap’s lemon coloured stage altogether.
Distribution and habitat
Aerangis citrata is widely distributed in Madagascar. Plants flourish in the evergreen forests across the Eastern side of Madagascar. Specimens occur at a range of altitudes, from sea level, all the way up to 1,500m. On occasion, this miniature orchid species can be sighted growing upon trees that have colonised higher areas of ground. Aerangis citrata plants are almost always found growing near water.
Aerangis citrata is an epiphyte. An epiphyte is a plant that grows upon another plant. This orchid is not a parasitic plant – it does not take any sustenance or nutrients away from its host plant; the host plant is not harmed or weakened by the orchid’s association. Aerangis citrata simply takes advantage of the opportunity that the host plant presents, using its host to raise itself up to a higher level within the forest canopy; thereby allowing this miniature orchid to enjoy improved air circulation and optimum growing conditions.
In the wild, Aerangis citrata plants colonise both the branches and trunks of the trees in Madagascar’s evergreen forests. To mimic the plant’s natural growing habit, I grow my Aerangis citrata plants mounted onto cork bark or tree branches, as well as on slabs or pieces of wood; the latter two mounts might not look as attractive but they allow me to cultivate more plants within a smaller area. Some growers prefer to cultivate this orchid species in a pot, but I opt to grow all of my Aerangis citrata specimens on mounts.
Aerangis citrata size
No official size measurements or categories exist for orchid size groups, but most nurseries and growers would class Aerangis citrata as a miniature sized orchid.
The plant you see pictured here in this article is a mature, flowering size specimen. When I took these photographs, my plant had nine leaves. Aerangis citrata’s fully grown leaves measure 7cm (2.8 inches) in length; while my plant’s long, fine roots measure 45cm (17.7 inches) in length. For its latest flowering, this plant produced four flowering stems; these ranged in size from around 11cm (4.4 inches) to 27cm (10.6 inches).
Aerangis citrata leaves are smooth with a slight sheen; they’re a rather lovely bright leaf-green colour. The inflorescences are densely flowered; many individual flowers are produced on each flowering stem. Each bloom measures around 2cm (0.7″) and is soft yellow, cream, ivory, or white, in colour. The rounded or fan-shaped lip is distinctive, as is the small dorsal sepal; while the flower’s nectary or spur measures around 3cm (1.2″) in length.
Aerangis citrata growing conditions
Aerangis citrata is happiest when it’s grown in a very humid environment of 75%RH or higher. I grow my Aerangis citrata plants inside terrariums, where I can maintain the high humidity levels my plants require. Aerangis citrata favours growing in an environment that provides continual air circulation around the plants and their roots.
Aerangis citrata plants produce very thin, fine roots. I have found that my plants grow best when they are misted early in the morning with rainwater, deionised water, or reverse osmosis water. I feel that it’s best to mist plants early in the morning, as the timing mimics the moisture deposited by early morning dew on wild plants. Consequently, my plants are often misted at dawn, this gives the plants, and their roots, plenty of time to dry out before nightfall, which is also important for optimum plant health. I believe that early morning misting is vital, if you want to cultivate happy, healthy plants.
My Aerangis citrata plants were misted by hand once in the mornings, for a minimum of five, and up to a maximum of seven, days a week. Since I moved my Aerangis citrata plants into terrariums with automated misting units, my plants are now all misted seven days a week.
This miniature orchid species is happiest growing near water. Aerangis citrata plants flourish in a very humid environment. For optimum plant health, this orchid species requires continual air movement and good air circulation, combined with regular, early morning misting – this is the key to growing Aerangis citrata plants successfully.
Like many of the orchids I grow, Aerangis citrata does not wish to be grown under a very bright or intense light; harsh lighting is to be avoided at all cost. Aerangis citrata flourishes in areas that benefit from soft or filtered light. I grow my plants inside terrariums, using LED lights to imitate daylight on an overcast day – an intensity of around 3,000 lux.
Aerangis citrata does not do well when it’s grown in too bright a location. Generally speaking, this is not a miniature orchid to grow near the top of your terrarium, where it’s closest to the lights. If you’ve read my Madagascan Orchid Trial, where I chose to position an Aerangis citrata specimen (the plant that you see pictured in this article) near the top of my Madagascar BiOrbAir Terrarium – my previous sentence may sound like quite a contradiction! However, I have found that the BiOrbAir’s LED lights produce a soft light. This terrarium’s LED lights produce a light that’s the same colour temperature as daylight. It’s not a harsh light, it’s not liable to scorch or harm Aerangis citrata‘s leaves.
The Aerangis citrata specimen that was previously grown inside my Madagascar Terrarium benefited from growing in very close proximity to this terrarium’s fan. As a consequence, this particular specimen enjoyed optimum air circulation around the plant and its roots, but the plant’s roots also dried out rapidly. To make matters worse, while this Aerangis citrata plant was growing inside my Madagascar Terrarium, this specimen was reliant on someone being around to hand mist it – hence at times this miniature orchid was very dehydrated. I have since moved this Aerangis citrata specimen into my new Tall Orchidarium, where the plant benefits from LED lighting, fans continually circulating the air, while automatic misting unit that mists the plants every day, without fail.
I’d advise growing Aerangis citrata in shaded to medium, diffused light conditions, far away from any sources of harsh or bright light.
Aerangis citrata is a cool to warm growing orchid species. In its natural habitat, in Madagascar, this orchid species experiences temperatures that range from a night-time minimum temperature of 10-17C (50-62F), to a daytime maximum temperature that ranges from 20-28C (68-82F), depending on the time of year.
My Aerangis citrata plants are grown in terrariums inside my home, where the minimum temperature never falls below 15C (59F) in winter. The maximum temperature, during the hottest days of summer, is usually under 28C (82F).
Providing your plants with optimum moisture
Aerangis citrata plants produce fine, thin roots. Naturally, Aerangis citrata’s preference for growing in an environment with continual air movement could lead these plants to become dehydrated very quickly, if sufficiently high humidity levels and regular misting were not provided.
My Aerangis citrata plants have been severely dehydrated on a number of occasions. Happily, this is a resilient orchid species, which has appeared to rejuvenate itself fairly quickly, once the plant’s ideal care programme with more frequent misting, (on average from five to seven mornings a week) was reinstated.
The other orchids that were grown inside my Madagascar Terrarium with this Aerangis specimen didn’t want to be misted as frequently as Aerangis citrata. Consequently, I was continually juggling each plant’s care, which usually resulted in none of the plants inside my Madagascar Terrarium being particularly happy, at the best of times. This has been tempered with many regular occurrences of every other plant inside this enclosure teetering on a precipice of being so over watered that I’ve risked sacrificing the lives of a number of orchids, in order to maintain one plant, pretty poorly.
As a consequence, I decided to empty my Madagascar Terrarium. I’ve had a rearrange; I’ve moved my miniature Madagascan orchids into new enclosures, to ensure that all of my miniature orchids receive their preferred growing conditions. I hope these plants will soon be happier and healthier.
In the wild, Aerangis citrata plants have adapted to growing in a slightly less humid environment over the winter months. Humidity levels in Madagascar may drop from 75%RH or higher, to lows of around 65%RH, in winter. I would describe Aerangis citrata as a plant that requires continual care – high humidity, good air circulation, and regular, frequent misting, throughout the year.
If you’re wondering whether you’re providing your Aerangis citrata plant with sufficient moisture, I’d recommend that you take a look at your plant’s leaves. Dehydrated leaves are naturally wrinkled, pliable, and lack-lustre. In direct contrast to fully hydrated Aerangis citrata leaves, which are much lovelier, they’re turgid, smooth, and glossy.
Aerangis citrata flowering
Aerangis citrata is a floriferous orchid species; in the wild, plants flower from early springtime until mid-autumn. While in cultivation, I have found that my Aerangis citrata plants flower in any season; blooming as frequently as around three times a year.
Inside my home, Aerangis citrata plants can bloom during any season. I make time to enjoy this orchid’s flowers’ fleeting beauty; for Aerangis citrata blooms don’t last long – they fade and disappear within six weeks of opening.
In Madagascar, Aerangis citrata flowers are pollinated by moths that are attracted to the nectar produced in the spurs of this orchid’s pale flowers. White blooms show up better than darker ones. As the light starts to fade in the early evening; white is the most visible of all flower colours from twilight onwards. Aerangis citrata inflorescences can look almost reflective, as they’re highlighted by the moonlight. These blooms have a crystalline quality, they can sparkle in the sun or moonlight.
Aerangis citrata scent
Aerangis citrata is often described as a fragrant orchid; usually the blooms are described as being lemon-scented. The Aerangis citrata specimen that you see pictured here in this article, has flowered many times in my care. Yet despite examining this plant and its flowers at every opportunity, at almost any time of the day and night, I have been unable to detect any perfume.
In the wild, Aerangis citrata receives all of its nutrients from the process of photosynthesis, from the air, rainwater, and any leaves, plant debris, or other materials that have collected around the plant. Aerangis citrata plants don’t receive large amounts of nutrients in the wild; therefore, it’s important to use a specially developed orchid fertiliser that reflects this and will not overwhelm your plant.
If your plant is currently resting and is not producing any new growth, don’t apply any fertiliser – just mist your plants with rainwater, deionised water, or reverse osmosis water. Take a break from applying any fertiliser until your plants start growing again. I’ve achieved good results using Orchid Focus fertilisers. I use Orchid Focus Grow – on plants that are actively growing and Orchid Focus Bloom – for plants that are in bud or in bloom.
This article was first published in the Orchid Society Of Great Britain Journal.
Other articles that may interest you…………
To see how my Tall Orchidarium was designed and set up, please click here.
To see how my Rainforest Terrarium was created, please click here.
To see a planting list of orchids, ferns, and other plants that are ideally suited to growing inside terrariums and bottle gardens, please click here.
To see the first part of my White Orchid Trial, please click here.
To see the first part of my Madagascar Orchid Trial, please click here.
To see the first instalment from my Miniature Orchid Trial, please click here.
If you’re interested, you can read about the fertilisers and general care I give my orchids in this article.