Chinese Rhubarb

Chinese Rhubarb

Some 50 species of stout perennials make up this genus, which is Eurasian in distribution. The two main medicinal species of rhubarb are R. palmatum, which reached Europe in 1762, and R. officinale, introduced in 1867. Both have laxative effects. Purgatives were historically of much greater importance thatn they are in medicine today. Various rhubarbs have been cultivated in China as medicinal herbs for over 2000 years and were recorded as imports by the ancient Greeks. For centuries, trade was controlled by the Chinese and Russians through the Kiakhta Rhubarb Commission, or Rhubarb Office, on the border between Siberia and Mongolia. This was abolished int 1782 after Europeans succeeded in obtaining live plants and cultivating domestic supplies. The cultivation of R. palmatum was given high priority int he 18th century. A map of the Royal Botanic Garden Edinburgh (originally a physic garden), dated 1777, indicates a very large area devoted to its cultivation. Rheum palmatum, one of the most widely used Chinese herbs, was first mentioned in the Shen Nong Canon of Herbs, which dates back to the Han dynasty (206BCE-CE23). Many common names exist, such as "Turkey Rhubarb" and "Dutch Rhubarb", which usually refer to a trade source, rather than the origin of the wild plant. Rhubarbs contain anthraquinone glycosides (as found in Rhamnus species, See, Buckthorn), which act as strong laxatives. Several other species are used medicinally, including R. australe (Himalayan Rhubarb, Indian Rhubarb), and the hybrid R. palmatum x R. coreanum (Japanese Rhubarb). These rhubarbs vary slightly in chemistry but are used interchangeably. Only the roots are used. The leaves are poisonous. The familiar edible rhubarb was derived from R. rhabarbarum (syn. R. rhaponticum), developed through hybridization during the 19th century. The roots of edible rhubarbs are not used for medicinal purposes.

Robust perennial with a thick rhizome, thick, succulent leaf stalks, and rounded, palmately lobed, jaggedly toothed leaves, to 90cm (36in) long, with maroon undersides. Tiny star-shaped, buff-green to deep red flowers are produced in a spire-like panicle in summer, followed by 3-winged fruits.

Common Name:

Chinese Rhubarb

Other Names:

Chinghai Rhubarb

Botanical Name:

Rheum palmatum

Genus:

Rheum

Family:

Polygonaceae

Native Location:

NW China and NE Tibet

Cultivation:

Well-drained, moist, rich soil in sun.

Propagation:

By seed sown in autumn (species and varieties only); by division in early spring.

Harvest:

Rhizomes are lifted in autumn from plants at least three years old and dried for use in decoctions, dry extracts, powders, tinctures, and tablets.

Variations:

Atrosanquineum
Syn. Atropurpureum
Has bright red buds, red-purple young leaves, and cherry-red flowers followed by pink fruits.

Var. tanguticum
Has jagged leaves, red-green when young, and white, pink, or red flowers.
Height: 2m (6ft)

Height:

2.5m (8ft)

Width:

1.8m (6ft)

Hardiness:

Z5-8

Parts Used:

Rhizomes (da huang)

Properties:

A bitter, astringent, cooling herb that improved digestion, stimulates the uterus, promotes healing, and has a laxative effect.

Medicinal Uses:

Internally for chronic constipation, diarrhea, liver and gall bladder complaints, hemorrhoids, menstrual problems, heat-related symptoms (such as nosebleed), and skin eruptions due to the accumulation of toxins. Externally for burns. Used in Homeopathy for irritability and teething in children.

Warning:

Leaves are harmful if eaten.
Contraindicated during pregnancy and lactation, and for intestinal obstruction.

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