Cypripedium japonicum is a widespread terrestrial orchid species in Japan, found from all four of its main islands – Kyushu and Shikoku in the south, the largest island, Honshu, and Hokkaido in the north. In olden times massive colonies dotted mountain forests, each being literally thousands of flowering stems strong. Nowadays, colonies are far fewer in number and largely protected and cared for. Out of all those innumerable plants that once graced the wet woods of Japan, a few were pure white flowers – the true alba variety of this species. A few still remain, but virtually all in cultivation these days. It is said that at least two known groups of this rare variety hail from Japan – one from the Nagano area of Honshu and the other from Shikoku. These alba plants are indistinguishable from the typical one except that the flower is completely free of any purple or pink coloring. They lack the anthocyanin pigments that normal flowers have in abundance.
Usually, I am not that drawn to true alba flowers, but in the case of this species, I take exception. Without a doubt this is one of the most elegant white flowered Cypripediums in the world.
As with many alba flowering plants, these do indeed seem to be weaker in cultivation that the normal type. In my experience they don’t hold up as well, being more given to rots. Beyond that, their requirements are the same as normal Cypripedium japonicum – a shady spot in the garden, a rich, humusy loam soil, and plenty of moisture year round. This species is completely intolerant of drying any time of the year. The same could be said for just about any Cypripedium, but with this one it is absolute – if you let them dry out, they will go dormant, weaken, and perhaps die. They are strong feeders, though I would fertilize only with annual addition of organic matter rather than inorganic salt based fertilizer, particularly if you are growing them in a highly organic compost to being with. It is all too easy to over fertilize terrestrial orchids, and they usually reward you by dying outright.
Perhaps the greatest hurdle in growing this plant is simply finding one. Outside of Japan they are nearly ghosts. Stories circulate of plants that have made it to Europe, but nobody is selling any on the open market. In America, if they exist at all, they are secreted away in some private collection. Even here in Japan they are not common and when offered command an impressive price. Before the economic meltdown of 2008, an individual flowering sized division would fetch between $600 and $1000 US. Nowadays with people holding onto their cash they go for as little as $350 for the same flowering division – if you can find one for sale.
Why so expensive? The simple reason is nobody has found a reliable way of propagating them other than by division. Cypripedium japonicum is notoriously difficult from seed, even using green pod rescued embryos. Perhaps one day someone will find a way, but for now this queen of lady slipper orchids will remain rare, illusive, and highly sought after.