Plant Encyclopedia

A miniature terrestrial orchid from Japan, Ponerorchis


Japan is home to many miniature species of orchid, but few come close to Ponerorchis graminifolia it terms of showiness.  It is so lovely in fact that plants in the wild are all but gone these days from over collection.  Luckily, it has proven to be fairly easy to grow and so today there are many varieties to choose from.

Ponerorchis graminifolia is a dwarf herbaceous perennial orchid of craggy rock ledges.  The entire plant rarely exceeds 15 cm in height.  The grass-like narrow leaves number between 3-6 per growth and occur alternately opposite each other on a thin, yet strong stem.  The glaucous leaves are longest at the bottom and tapper off to very short, almost bract-like affairs at uppermost (near the flowers).  They can be bright green, deep green, or striated with purple streaks depending on the variety and are between 2-10 cm long each.

 

Ponerorchis graminifolia plants

Another fancy selected form of Ponerorchis graminifolia. The leaves are grass-like, hence the name graminifolia which means, "grass leaf".

 

 

The flower stalk continues on from the last leaf for a considerable distance (up to half the entire height of the plant) and bear anywhere from 1 to 20 flowers.  The flowers are small, no more than 2 cm on average.  Each flower has an attending bract, but are so small so as to be almost unnoticeable.  Naturally occurring plants have flowers with a deeply trilobed lip, back flung, narrow sepals, and a hood-like structure composed of the dorsal sepal and petals covering the column.  The flower also boasts a conspicuous spur that is usually fairly straight in the wild forms, but tends of be hooked in many of the cultivated varieties. Typical flower color is pinkish with purple striations on the lip in particular.  Variation in cultivated forms is extreme as you can see in the photos.

 

 

 

 

Ponerorchis graminifolia wild type

This flower is a wild type form of Ponerorchis graminifolia. The lip is much reduced in size and the flower is a bit smaller than selectively bred ones.

The roots are few, fleshy, and relatively short. They last only one growing season.  The plants grow from underground light brown tubers that look like little potatoes.  Their shape is anything from round to elongate to forked (hence the name orchis meaning “testicle”) and range from 1-8 cm long. These can increase from year to year considerably with a vigorous plant producing 3 or more new tubers from one parent tuber.  Again, these last just one growing season feeding the new growth and flowers.  So, the underground portion of the plant is completely renewed each season, as are the above ground parts – a fact that is truly amazing when you think about it.

Its native habitats are rocky crags and cliffs, growing by clinging to rock faces or in the cracks of rocks in relatively low mountains.  Their native range is throughout Japan south of Hokkaido, and nowadays the species is vulnerable or extinguished.  A few localized forms exist and are in great danger of going extinct in the wild: v. kurokamiana (Nagasaki), v. micropunctata (Kagoshima), and v. suzukiana (Chiba).  One source quotes that the wild population of v. kurokamiana, found only on Kurokami Mountain, has been reduced by at least 90%.

 

Ponerorchis graminifolia bulbs

In the fall the top growth dies and the new bulbs are fully formed. Here you can see the remaining roots as well as the old bulb now spent.

Wild plants are imperiled due to over-collection rather than habitat loss, as is the case with many desirable native orchids.  I have tried finding them in places they once grew only to be disappointed.  I’ve inquired about this to various people and they invariably say the same thing, “oh yes, they used to grow there, but they have all been taken by now.”  What is remarkable is the trouble folks must have gone through to get them since they often grow in places that are only accessible by using climbing ropes.  I’m sure that some out of reach niches still harbor a few.  Still, one day I hope to find some on a rocky crag, and with luck I won’t fall over the edge trying to photograph them!

The good news about this plant is that it is pretty easy in cultivation provided you follow a few guidelines.  First of all, they need really good drainage.  I grow mine in pure kanuma, a volcanic material that is much like perlite, but acidic in reaction.  The bulbs are planted so that the top end is just below the surface with a bit of sphagnum moss put around them to retain moisture, but I add no other organic matter.  Growers in other places have reported good success with much more organic composts using such things as bark, peat, and humus. I avoid all that due to rot problems in Japan’s hot and humid climate.

 

Ponerorchis graminifolia Large Lavender

This large flower form was achieved through selective breeding. The lip in particular is much larger than the wild types.

Ponerorchis graminifolia white

Ponerorchis graminifolia - a lovely pure white form.

 

 

 

 

 

 

 

 

 

 

 

 

They like bright light, but not much sun (a little in the morning is OK) and humidity must remain high at all times.  Water generously while in flower (June and July), then back off a bit while still keeping them moist until dormancy sets in.  Beware, do not truly dry them out, just be cautious with over-watering at this time since rot could ensue.  They like a long growing season from late April to late October.  Fertilize with a weak solution every few weeks, until September and then back off.  By mid November they should be dormant.

Ponerorchis graminifolia Butterfly

Ponerorchis graminifolia - a form I call "butterfly".

During dormancy I used to remove the plants from their pots and collect the new tubers for winter storage.  Nowadays I simply dry the pot out almost completely, but sprinkle a bit of water on them from time to time.  Don’t let them get baking dry though.  In the spring I replant them in fresh media to ensure protection from the break down of the sphagnum.  In truth you can probably get away waiting every other year or so to repot, but I err on the careful side.

The temperature in winter should be above freezing with an average temperature of less than 10 C (50 F).  Their cold hardiness is questionable – I would say that USDA zone 8 is fine and probably zone 7 is OK as well.  Colder than that and you had better mulch them in very deeply.  In the wild I’m sure they never seen anything but superficial freezing of the soil, so be careful.

Ponerorchis graminifolia pink

The range of colors achieved through breeding is astounding. I call this one "pretty pink" - definitely a girly flower!

 

 

 

 

This plant is one of Japan’s natural jewels.  To appreciate them you have to get close to get a good look since they are true miniatures.  The range of colors and forms that have been bred these days is beyond belief – a far cry from the wild forms.  Moreover, considering they are terrestrial orchids, they have proven to be fairly straightforward in cultivation – not a common trait with this group of plants.  If you love miniature orchids, I highly recommend you find a few.

 

 

 

 

 

 

 

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