Three Calanthe from Japan’s southern mountains

In the warm temperate woods of southern and central Japan exist two beautiful terrestrial orchids, Calanthe discolor and C. sieboldii, as well as their natural hybrid, C. x bicolor.  C. discolor still exists in some quantity in the wild, but C. sieboldii as well as their hybrid have been collected almost to the point of extinction.  Even to this day plants routinely “disappear” from their mountain homes, often ending up for sale at roadside vendors and orchid shows.  Let’s have a look at the most common of the three first, C. discolor.

C. discolor is a conspicuous and showy orchid species.  The leaves are evergreen and deeply ribbed giving them a pleated look.  Each is 10-30 cm long and 5-10 cm wide.  Most growths have only two leaves, but as many as four are possible.  The relatively small subterranean pseudobulbs are round and have ribs, growing in a chain, so people thought they looked like shrimp, hence the Japanese name ebine, meaning literally “shrimp root”.

Calanthe discolor, dark and light colored forms
These two Calanthe discolor growing side by side show the two ends of the flower color scale for this species..

From the center of each growth a branch less flower stalk arises to the height of 15-35 cm and can sport anywhere from 5 to 20 bicolored flowers. Each flower is about 3 cm across and has a rounded look with the sepals and petals being the same color and similar in shape and size. The lip is three lobed and a different color.  The lateral lobes are broad, with rounded edges and are smooth.  The central lobe is lightly to deeply ribbed with varying numbers of protrusions.  It is often lobed at its end as well.  The column is large and knob-like and is usually the same color as the lip.  Flower color can vary widely with the typical flower having a white lip with pale purple markings (sometimes yellow as well) and the sepals and petals being a shade of greenish-brown.  Having said that I’ve seen flowers ranging from the typical type to ones with pure white lips with green sepals and petals, others with purplish lips with chocolate brown sepals and petals, and ones completely suffused with purple.

Calanthe discolor flower types
The flowers of Calanthe discolor are highly variable in color and form.

This species grows in a variety of habitats including wet to moist woodlands, conifer plantations, along mountain streams, on tops of mountain ridges, and on seepage slopes.  It can be found throughout the warmer temperate regions of Japan from Kyushu to southern Hokkaido.  Plants can be single growths or make large clumps in time with 20 or more flowering stems.

This is the most widespread and common species of Calanthe in Japan.  It is capable of living in a diverse range of habitats, and is one of the few orchid species that can live in tree plantations.  The flowers are often, but not always, showy.  Many are pale, greenish and white in color, and therefore easy to miss in the dim forest light.  Others are remarkably beautiful and highly coveted by plant collectors.  It is unfortunate that in this day where micropropagation of terrestrial orchids is common, plants are still being taken from the wild. Those near trails are most vulnerable and in the 9 years I’ve been watching they continue to diminish in number year by year.  Many of these end up at roadside markets or are sold on internet auctions.  Some years ago, I found a large colony with a great variety of color forms, huge clumped plants, and even the natural hybrid between C. discolor and C. sieboldii, C. x bicolor.  The plants are OK so far, but I wonder how long they will remain unharmed.

Calanthe discolor purple flowered form
This lovely purple flowered form of Calanthe discolor growing on a local mountain has been collected. A similar plant nearby was taken a few years later.

I’ve seen catalogs full of Calanthe for sale, including many wild species.  How many of these were wild collected?  Very likely all of them.  In spring roadside vegetable markets offer plants for relatively high prices and they often have poor quality flowers.  This definitely points to the probability they were wild collected – why would you propagate a poor flower?  Still, given the plant’s ability to grow in many places over a wide range, their future seems fairly secure for the time being, but for how much longer?  I would say that easily accessible populations have reduced by close to 50% locally over the past 9 years.  That’s a pretty scary statistic.

C. sieboldii is a much bigger plant than C. discolor.  The leaves are similar to C. discolor, but larger, up to 15-40 cm long and 8-15 cm wide.  The flower stalk arises to the height of 45 cm or more and can sport anywhere from 5 to 25+ yellow flowers.  Each is about 3-5 cm across and uniformly colored pale yellow to brilliant lemon yellow.  The sepals and petals are more pointed than in C. discolor and longer.  The lip is three lobed with the lateral lobes being broad, and having rounded smooth edges.  The central lobe is lightly to deeply ribbed with varying numbers of linear protrusions.  It is often lobed at its end as well.  The column is large and knob-like.  Some plants also have red-brown markings on the underside of the column and on the protrusions of the lip.

Calanthe sieboldii flower spike
Calanthe sieboldii is certainly a showy orchid, one of the most conspicuous in Japan.

In all respects the plant is very similar to its near relative C. discolor , but is usually larger in size and more spectacular. The flowers can be very sweet smelling, while others have just a trace of scent.  Plants can be single growths or make large clumps.

This species prefers wet to moist woodlands, along mountain streams, and seepage slopes, and even is reported from high mountain meadows in tall grass.  It is found only in the warmer parts of western Japan from Kyushu and Shikoku to western Honshu (Shimane, Shizuoka, Wakayama, and Yamaguchi Prefectures), and some islands just off the coast.  It has also been reported from the southern end of the Korean peninsula.  A larger growing variety, v. kawakamiense, is found on Taiwan and some consider it a separate species.  It certainly is large, with heights up to one meter tall recorded.

This is one of Japan’s most spectacular terrestrial species, and truly lives up to the Greek derived name Calanthe, meaning “beautiful flower”.  It lovely both in and out of flower, the flowers are long lasting and gorgeous.  There really is nothing negative you could say about it.  Unfortunately, this has lead to its demise in the wild since plants are under heavy collecting pressure throughout its range (I’ve heard this from all sources).  In fact, I’ve only seen it once in the wild on a very popular mountain in the Fukuoka area, and that plant has been poached. In May 2004 I was walking up a steep slope in a little ravine when I came across a large two growth plant on the brink of a stream.  I was both surprised and greatly pleased to have the chance to see this rarity, and was further rewarded a short time later when I found a colony of green flowered C. x bicolor just upstream.  That was a banner day!

Calanthe sieboldii Flower
The flowers of Calanthe sieboldii are unmistakable – large and yellow.

The next spring I eagerly returned to photograph the plant again, but when I got to the little bend the stream where the plant had once been, all I found was a hole, a few broken roots, and some old leaves.  It had been collected perhaps just a few days or hours earlier.  I was fuming mad.  Being in a hurry that day, I couldn’t find the C. x bicolor colony either.  I wasn’t worried though since those plants were farther from the trail in a very difficult to reach spot.  In May 2006 I went back and searched for the plants, and after hours of combing the entire area, I found nothing.  Apparently these too were taken, probably at the same time as the C. sieboldii.

Here’s a video of me looking for this species in the wilds of Fukuoka Prefecture in 2013 – in the vid you’ll get to see many plants in the local area plus whether or not I found any C. sieboldii

Calanthe sieboldii clump
Calanthe sieboldii growing in the author’s garden. At the bottom you can see C. x bicolor as well – much smaller plants!

I used to live in an apartment complex in the shadows of that mountain, and there was a large bed of C. sieboldii in the front garden.  It is very likely they were taken years ago from the same mountain.  Given this situation, the species’ future in the wilds of Japan is dim indeed.  It will no doubt grace the gardens of this country for years to come, but few will dwell in their mountain homes except in the most remote locations.  On a brighter note, I have cross pollinated several of my plants and they readily set seed.  The seeds have been sown into known Calanthe locations in hard to access areas in the hope to get this plant going again in the woods of Fukuoka.

C. x bicolor is the natural hybrid between C. discolor and C. sieboldii, and is very similar in appearance to its parents.  The difference can be seen in the flowers. These are often similar in shape to C. sieboldii, but they are usually light yellow and red-brown.  The sepals and petals are typically one shade of red-brown with some plants being darker than others.  The lip is commonly light yellow, but can be pale to the point of appearing almost white or a darker yellow like its parent C. sieboldii.  The lip can also have varying amounts of red-brown markings.  Having said all that, the plants can have flowers that look identical to either parent.  Furthermore, pure green forms exist as well!  Yes, it is confusing, but when you see an intermediate plant (as the ones pictured here) it is easy to recognize that it is a hybrid.

Here’s another video of searching for C. sieboldii in the same valley as the above video, plus a mixed colony of C. discolor and C. x takane on another mountain:

Calanthe x bicolor flowers
Calanthe x bicolor growing on a local mountain. This form is intermediate between the two parents, but one cannot consider it “typical” since great variation exists between plants.

This hybrid is found where both parent species are present, that being the warmer temperate regions of  western Japan from Kyushu and Shikoku to western Honshu (Shimane, Wakayama and Yamaguchi Prefectures), and possibly also South Korea’s southern end.

This plant has caused quite a bit of confusion.  It is often listed as a variety of C. discolor, and for a long time it was considered synonymous with C. sieboldii (actually, until recently C. sieboldii wasn’t recognized as an official taxon and therefore both the hybrid and C. sieboldii were placed under the species C. striata).  One thing is certain, these plants do exist in nature and in places where both parents are potentially present.  Taxonomy aside, the plant itself is very distinctive, and there is no doubt of its identity when you see one.  This hybrid is also sometimes sold under the name  C. x Takane to further confuse all concerned.

Calanthe sieboldii seed pods
The seed pods of Calanthe sieboldii are typical for the genus.

I have been lucky to find a small group flourishing beside a large colony of C. discolor on a mountain nearby my house.  I have seen no plants of C. sieboldii in the immediate vicinity.  What does that mean?  There are three possibilities:  maybe pollen was brought from a distant plant by a pollinator, perhaps the C. sielboldii plants were collected from the site, and finally, perhaps I just haven’t found the “missing” plants yet.  Folks from the area tell me that several of the local mountains used to be covered in Calanthe, including C. sieboldii, but that was 30 or more years ago.  Recently, I’ve been told of a surviving colony on a more distant mountain, but I wonder how long it will persist.

Fortunately, all three are easy to grow and bloom.  Like most terrestrial orchids, they like a well draining yet water retentive growing medium.  I grow mine in a mix of coarse pumice (0.5-1.0 cm diameter), bark, and a little humus.  I don’t use more than 30% organic material to avoid rot problems.  They can grow in very wet conditions in the wild, however that isn’t necessary or advised in cultivation.  Don’t give them any sun, but rather a nice cool shady place (anywhere woodland ferns like, these will like too).  They are also excellent garden subjects requiring no special treatment, provided the bed is well constructed.

Calanthe x bicolor in habitat
Calanthe x bicolor in habitat, Fukuoka Prefecture, Kyushu, Japan.

Any reasonable fertilizer can be applied, starting just after flowering and continuing into mid fall when the plant is forming next year’s growth and flower buds.  I use pelleted organic fertilizer that is pretty mild.  They are fairly cold hardy, certainly through USDA cold hardiness zones 7-9, and even colder with adequate winter mulching.  It is important to note that these are temperate plants, and require a true winter cool down with temperatures averaging 10 C (50 F) or lower for 2-3 months.  C. sieboldii is supposed to be more cold sensitive, however I’ve heard of reports of people growing them in USDA zone 6 in America with lots of winter mulching.  In time all can grow into nice clumps.

There is one issue with Japanese Calanthe that has to be taken very seriously – virus.  This is an uncomfortable topic with plant growers since a virused plant left alone in a collection can literally kill every plant within a short time.  Suffice it to say, if you see extreme anomalies in flower color, especially streaking or color breaks, or more importantly, if you see white, linear streaking on the leaves, then that plant should be destroyed immediately.  Either throw it away in the domestic trash (don’t compost it!) or burn it on an open fire.  The compost too should be thrown away and the pot destroyed as well or put into a strong bleach solution.

Never prune Calanthe plants without heat sterilizing the scissors or shears when moving on to another plant.  Spotting on the flowers (usually a paler color) commonly happens when water gets on the buds and isn’t an indication of virus.  This is a complicated topic and deserves an article of its own.

Calanthe sieboldii in habitat
This is the only Calanthe sieboldii I’ve ever seen in the wild. It was poached in 2005. (Check out the video above to see an update on this species in the Fukuoka area).

Despite the problem of virus,these plants are truly rewarding and relatively easy to grow in a warm, humid climate or as a greenhouse plant.  If the proper care is taken, they rate as a fairly easy to grow terrestrial orchid.


9 Replies to “Three Calanthe from Japan’s southern mountains”

  1. Hello BotanyBoy,

    Can Calanthe sieboldii be pot grown as a house plant? You mentioned above that it can be grown as a greenhouse plant so I assume it can be grown as a house plant. And can this species be acquired from virus-free propagated stock, not wild collected? I don’t believe in ripping off plants from the wild even though propagated ones originated there.

    Thank you in advance for your reply.


    Michael Davenport

    1. Hi Michael,

      Though I never say never, I would only suggest that indoor cultivation of this species could be difficult. It requires seasonal variation including a rest period of no less than 3 months with temperatures averaging below 50 F (10 C). Perhaps if you have an unheated windowsill where you could place it in the winter months, you may be able to grow it successfully. Calanthe are easily pot grown, in fact they seem to do better in pots than in the ground, at least here in Japan. Plants bought outside of Japan are most likely not wild collected, but rather micropropagated in flasks, so there shouldn’t be a problem there (one hopes!). Good luck.


      1. Thank you again Tom. I think i’m going to try this species. There is a nursery here in the states that sometimes sells this plant.

        This species look very beautiful vegetatively and flowers would just be a bonus. I have a well lit garage that may have temperatures as low as 50F in the winter time though I haven’t measured that and alternatively I have a porch that definitely gets cold though it is less well lit.

        If this nursery can acquire some for sale, I should know in January when their catalogue comes out and if I can get this species I’ll let you know how they do if you are interested.


      1. Yes, nowadays many evergreen Calanthe species from east Asia are available around the world. Unfortunately, in the wilds of Japan they are becoming more scarce with time.

  2. After watching the orchid show video with the Calanthes, I completely fell in love with them. I even got a Dendrobium Moniloforme. I was lucky enough to get my hands on five Calanthes that I really liked. I purchased a Takane, a Discolor and three Kojimas. I plan on growing them indoors in pots. I can only hope my basement gets cold enough for these orchids to go dormant and thrive next year. So far so good.

  3. Hi, in 2015 I was fortunate to get a division of Calanthe Kawakamiense from a fellow orchid grower in England.
    His plant has not flowered since he divided it and neither has mine.
    It hardly grows, but is still alive with two leads. I keep it above 5C in the winter and stand it in my garden in semi shade after frost has passed and before it gets cold.
    Please, can you suggest what I should do to make it happy.

    1. Keep it moist year round, drop the temperatures to not above 10 C from December thru March, water it copiously in spring, summer and back off water a bit in fall and winter, and during the growing season fertilize it regularly. It may be your plant is just not being fed enough. Also, repotting seems to help with sluggish plants. This one is just a form of C. seiboldii (AKA striata) from Taiwan, so it may like slightly higher temperatures in winter, say anything above -3 C and never truly frozen compost. Good luck!

  4. Nice informative article. I have difficulties growing these Calanthe in the Netherlands. One problem is anthracnose leaf rot in new sprouts of sieboldii and Takane Lemon Lime in spring. It seems to be caused by humidity and water and I can’t put them outside where they can get wet. The discolor and Kozu that I also have don’t have this issue and are fine outside, but last year had rather yellowish streaked leaves suggesting a magnesium deficiency. This year I only had a few flowers on all. They are all grown in pots in a substrate of cocopeat mixed with leaf humus and perlite. I feed them with orchid fertilizer. I wonder if both problems are due to a mineral deficiency. In your article it is said that they grow along streams and on seepage slopes in forests. Are the soils rich in calcium and minerals there? What kind of rock are the mountains composed of? Volcanic? Perhaps the ph of my substrate is too low? Should I raise the calcium and magnesium content of the substrate by adding some dolomite lime? Are sieboldii and hybrids with it more susceptible to diseases? Japanese Calanthe have been mass cultivated in greenhouses by an industrial Phalaenopsis nursery in the Netherlands and have been marketed sold as “garden orchids” in garden centres in spring for several years, but they are definitely not as easy to grow here as the nursery claims. Any suggestions will be appreciated.

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