Herbs & Plants

Arisaema thunbergii

Botanical Name: Arisaema thunbergii
Family: Araceae
Kingdom: Plantae
Genus: Arisaema
Species: A. thunbergii

Synonyms: Flagellarisaema thunbergii.

Common Name: Asian jack-in-the-pulpit, Cobra lily

Habitat:Arisaema thunbergii is native to E. Asia – Japan. It normally grows in forest area, at elevations of 20–100 meters.

Arisaema thunbergii is a herbiculas perennial plant, growing to 0.6 m (2ft). tall topped by a solitary horizontal leaf clad with 9-17 narrow lanceolate leaflets. A single flower emerges from the ground in spring (April-May) near the base of the leaf petiole. The flower consists of a pitcher-like spathe (white with purple-speckled stripes) with a pointed blade-like hood (dark purple to near black) that drapes forward over the top of the pitcher. Hooded spathe reportedly resembles the head of a cobra hence the common name. An inner cylindrical upright flower spike known as the spadix (white at the base changing to purple) has a long purple whip-like tail which emerges over the collar-like lip of the spathe and trails outward to as much as 24″ long.

It is in flower from April to May. The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). and is pollinated by Flies. The plant is not self-fertile.

Plants go dormant in summer after flowering, except some plants will produce a cluster of berries in mid-summer which become visible as the spathe withers. Berries ripen to red. Stalks, leaves, flowers and fruits give this plant a tropical aura. All plant parts contain calcium oxalate (same chemical as in Diffenbachia or dumb cane) and are poisonous.


Genus name comes from Greek words aris meaning arum and aima meaning red in reference to the red-blotched leaves found on some species.

Best grown in humus-rich, moist but well-drained soils in part shade to full shade. Needs consistent moisture. Does poorly in heavy clay soils. Plant tubers about 3-4″ deep. May be grown from seed, but may take 3-5 years before plant will flower. Winter hardy to USDA Zone 5 (perhaps 6) to 8. In the St. Louis area, it should be planted in a sheltered location.

Seed – best sown as soon as it is ripe in a shady position in a cold frame. Stored seed remains viable for at least a year and can be sown in spring in the greenhouse but it will probably require a period of cold stratification. Germination usually takes place in 1 – 6 months at 15°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 a coupe of years until the corms are more than 20mm in diameter. Plant out into their permanent positions whilst they are dormant. Division of tubers when the plant dies down in late summer.

Medicinal Uses: Alterative, anaesthetic, deobstruent, discutient, diuretic, expectorant, vulnerary. The root is used.

Known Hazards: The plant contains calcium oxylate crystals. These cause an extremely unpleasant sensation similar to needles being stuck into the mouth and tongue if they are eaten but they are easily neutralized by thoroughly drying or cooking the plant or by steeping it in water.

Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.


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