Common Name:

General Information

Cypripedium japonicum is a herbaceous perennial plant with a relatively slender, creeping rhizome; it produces 2 (rarely 3) leaves on erect flowering stems that are around 35 - 55cm tall[].
The plant is harvested from the wild for use as a medicine. It is grown as an ornamental in gardens.
Cypripedium japonicum is rare to extremely rare in some areas with a scattered and restricted distribution. The trend of the population is decreasing and the abundance of the species has been significantly reduced in recent decades due to many threats especially exploitation for horticultural and medicinal purposes, ruthless collection, trampling, weak recovery, frequent fires, overgrazing pressure, ecological disturbance, deforestation, tourism and infrastructure development.The plant is classified as 'Endangered' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

We have seen no reports for Eurasian members of the genus, but there are reports that the glandular hairs on the leaves and stems of some N. American species can cause a rash, similar to poison ivy rash[].
We have no specific information for this species, but it has been stated that the roots of at least one member of the genus may cause psychedelic reactions, and large doses may result in giddiness, restlessness, headache, mental excitement and visual hallucinations[].

Botanical References

Range

E, Asia - central and eastern China, Japan, Korea

Habitat

Edges of bamboo groves, montane and bamboo forest, Cryptomeria japonica forest, usually near streams and lakes and wet mature deciduous woodland on mountainous hillsides with Camellia japonica; at elevations from 1,000 - 2,000 metres[]

Properties

Conservation Status	Endangered
Medicinal Rating
Habit	Perennial
Height	0.45 m
Pollinators	Bees, Insects
Self-fertile	Yes
Cultivation Status	Ornamental, Wild

Cultivation Details

Cypripedium japonicum is a very cold-tolerant plant, when fully dormant it can withstand temperatures down to at least -20°c[].
Prefers a position in dappled shade[]. Found in the wild in well-drained situations in humus rich organic soils that range from acid to alkaline, growing in both limestone and peat bogs[].
Orchids are, in general, shallow-rooting plants of well-drained low-fertility soils. Their symbiotic relationship with a fungus in the soil allows them to obtain sufficient nutrients and be able to compete successfully with other plants. They are very sensitive to the addition of fertilizers or fungicides since these can harm the symbiotic fungus and thus kill the orchid[].
The flowers of Cypripedium species belong to the group of 'trap' flowers. An insect as it crawls in, can only escape from the slipper-like labellum through a tunnel near the base of the labellum from where it is directed first to the nearby stigma where possible pollinia from another flower on its back are stripped off and while escaping, sticky pollen from the nearby anthers adhere to its back for the pollination of another flower[].

Edible Uses

None known

Medicinal

The root is sedative and is used as a treatment for nervous disorders and as an official nerve stimulant[].

The herb is said to dispel wind, remove toxins, moderate qi, improve blood circulation and relieve pain. It is used in the treatment of tertian malaria, menstrual irregularities, pain arising from physical injuries and pruritus[]

Other Uses

None known

Propagation

Seed - surface sow, preferably as soon as it is ripe, in the greenhouse and do not allow the compost to dry out. The seed of this species is extremely simple, it has a minute embryo surrounded by a single layer of protective cells. It contains very little food reserves and depends upon a symbiotic relationship with a species of soil-dwelling fungus. The fungal hyphae invade the seed and enter the cells of the embryo. The orchid soon begins to digest the fungal tissue and this acts as a food supply for the plant until it is able to obtain nutrients from decaying material in the soil[]. It is best to use some of the soil that is growing around established plants in order to introduce the fungus, or to sow the seed around a plant of the same species and allow the seedlings to grow on until they are large enough to move.
Division with care in early spring, the plants resent disturbance[]. Remove part of the original rootball, making sure to keep some of the soil around it intact[].
Division is best carried out towards the end of the growing season, since food reserves are fairly evenly distributed through the rhizome[]. Small divisions of a lead and two buds, or divisions from the back (older) part of the rhizome without any developed buds, establish quickly using this method[]. Replant immediately in situ[].