Common Name: Nerve Root

General Information

Cypripedium acaule is a herbaceous perennial plant growing from a fleshy rootstock with short rhizomes; it slowly spreads to form a clump with leaves arisng directly from the rhizomes and leafless flowering stems growing around 15 - 60cm tall[, ].
With a high reputation as an effective sedative and nervine, this plant has been heavily harvested from the wild in the past for use as a medicine and was also gathered for horticultural purposed. It is less used medicinally (though no less effective) and is still grown as an ornamental in gardens.
Cypripedium acaule is widespread with a large distribution area and abundant populations. The existing threats to the species and its habitats are unlikely to cause populations to decline quickly in the near future and the future of the species would be secured if the conservation measures suggested are applied and public awareness is raised. The species is still so common that only a high level of collecting would impact populations beyond a very local scale. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2014)[].

Known Hazards

We have no specific reports for this species but, especially during the flowering season, the glandular hairs on the leaves and stems of some N. American members of this genus can cause a rash, similar to poison ivy rash[, ]. The irritation is usually minor, or only lasts for a few minutes[].
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

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Range

N. America - northern Canada (Northwest Territorie) through central and eastern N. America south to Georgia and Alabama

Habitat

Moderate shade on well-drained slopes of dry forests, especially pine but also deciduous and moist woods, often growing in humus mats covering rock outcrops, also in bogs, swamps, brushy barrens, heath, and roadsides; at elevations up to 1,200 metres[]

Properties

Conservation Status	Least Concern
Medicinal Rating
Habit	Perennial
Height	0.40 m
Pollinators	Bees, Insects
Self-fertile	Yes
Cultivation Status	Ornamental, Wild

Cultivation Details

Cypripedium acaule is a very cold-tolerant plant, when fully dormant it can withstand temperatures down to about -25°c[].
Requires a position in semi-shade on a damp acid soil that is rich in humus[]. Found in the wils on sandy soils that are rich in humus, strongly acidic and well aerated[]. Plants grow well in a woodland garden or shady border[].
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[].
Resents root disturbance[].
A very ornamental plant[], it is quite difficult in cultivation and plants will often flower well in their first year then disappear[]. This is possibly because the plants are sold bare-rooted and do not have the necessary fungal symbiant they need in order to thrive[]. Only buy pot-grown plants in order to try and ensure that the symbiant is present[].
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[].
The plants are subject to damage by slugs[].

Edible Uses

None known

Medicinal

The root is antispasmodic, nervine, sedative, tonic[, ]. It is said to be the equivalent of Valerian, Valeriana officinalis, in treating nervous complaints, sleeplessness etc[]. The roots have also been used in the treatment of menstrual disorders, stomach aches, kidney and urinary tract disorders and venereal disease[]. An infusion of the dried tuber is used[].
Traditionally, a root tea was used to treat worms, stomach ache, flu and neuralgia[].
The tubers are harvested in the autumn[].
The active ingredients are not water-soluble[].

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[].