Common Name:

General Information

Asarum gusk is a low-growing, herbaceous perennial plant producing a cluster of leaves up to 15cm tall from a creeping rootstock, The rather interesting, but unpleasant-smelling flowers are hidden amongst the leaves[].
The plant is harvested illegally from the wild for medicinal use and also to supply plants for cultivation[].
Asarum gusk grows as only one population on Amami-Oshima Island in the Nansei-shoto Islands, Japan. Its current population is estimated to be around 100 and its extent of occurrence (EOO) is estimated to be less than 100 km2. Illegal collection for cultivation and habitat change caused by logging has caused rapid decline of this species. Although it is protected, the threats are ongoing. The plant is classified as 'Critically Endangered' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

None known

Botanical References

Range

E. Asia - southern Japan (Ryukyu Islands)

Habitat

Forested slopes at elevations from 300 - 450 metres[].

Properties

Conservation Status	Critically Endangered
Medicinal Rating
Habit	Perennial
Height	0.10 m
Pollinators	Self, Flies
Self-fertile	Yes
Cultivation Status	Ornamental, Wild

Cultivation Details

Asarum gusk grows in an area with a humid subtropical climate with very warm summers and mild winters. Precipitation is high throughout the year, but is highest in the months of May, June and September. The area is subject to frequent typhoons. The plant is unlikely to succeed outdoors in any but the mildest regions of the temperate zone.
Plants in this genus generally prefer a rich moist neutral to acid soil in dappled to deep shade in a woodland or in a shady position in the rock garden[, ].
The flowers are malodorous and are mainly self-pollinated but are also pollinated by mycotrophic flies[, ].
In cultivation this species hybridizes with other species (the pollen is fertile with other species)[].

Edible Uses

None known

Medicinal

The plant is used medicinally. It is illegal to collect this plant from the wild because of its conservation status, but illegal collections still continue[].

Other Uses

None known

Propagation

Seed - best sown in a cold frame as soon as it is ripe in the summer[]. Stored seed will require 3 weeks cold stratification and should be sown in late winter[]. The seed usually germinates in the spring in 1 - 4 or more weeks at 18°c[]. When large enough to handle, prick the seedlings out into individual pots and grow them on in light shade in the greenhouse for at least their first winter. Plant them out when large enough in late spring.
Division in spring or autumn. Plants are slow to increase[]. It is best to pot the divisions up and keep them in light shade in the greenhouse until they are growing away strongly.