Common Name:

General Information

Asarum tabatanum 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 tabatanum is endemic to Amami-Oshima Island in Nansei-shoto Islands in Japan. It was described in 2012 when it was separated from Asarum celsum and its exact distribution is not fully known, but based on current knowledge it has one small population of around 30 plants. Illegal collection for cultivation and for medicinal use are major threats. Some of the peripheral habitats were clear cut in the past and the slopes have become extremely dry. This species is unable to grow in such dry conditions and it will be difficult for the population to recover if this situation continues. Although the species is designated as a protected species, the protection is not enough. 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

Slopes or ridge of hills covered by broadleaved forest[].

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 tabatanum 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[, ].

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.