Common Name: Himalayan Rhubarb

General Information

Rheum australe is a herbaceous perennial plant growing from a stout, woody, rhizomatous rootstock; it produces a basal clump of leaves up to 50cm x 40cm on stout petioles that are up to 50cm long; the plant flowers in the summer, producing flowering stems up to 150 - 200cm tall[, ].
The plant is harvested from the wild for local use as a food, medicine and source of materials. A very popular herbal medicine, the root is harvested in very large quantities from the wild and sold in local markets[, , ]. It is sometimes cultivated for medicinal use[].
Overgathering of this plant from the wild, both for food and for medicine, is becoming a cause of conservation concern[].

Known Hazards

The plant, but especially the leaf blades, contains several toxic compounds, particularly anthraquinone glycosides, but also soluble oxalates and calcium oxylate crystals[, , ]. At lower doses these can cause abdominal cramps, burning of the mouth and throat, headache, weakness, nausea and vomiting. In larger, quantities it can lead to coma and death, though generally very large quantities need to be eaten for the plant to be fatal.
The leaf stems (petioles) have much lower quantities of toxins and, in several Rheum species are a commonly eaten food. The main caution here are the levels of oxalates. These can lock up certain minerals (especially calcium) in the body, leading to nutritional deficiency. Cooking the plant will reduce the concentration of oxalic acid. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[].

Botanical References

, ,

Range

E. Asia - Himalayas from Pakistan, through Nepal and Tibet to northern Myanmar.

Habitat

Moist scrub, open slopes on rocky ground, alpine meadows, forest margins; at elvations from 3,200 - 4,200 metres[, , ]. Grassy slopes; at elevations from 3,400 - 4,300 metres in Tibet[].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	3.00 m
Pollinators	Wind
Cultivation Status	Cultivated, Wild

Cultivation Details

Rheum australe is a moderately cold-hardy plant, tolerating winter temperatures that can fall to about -20°c[].
Rheum species generally prefer a deep, fertile, moderately heavy, humus rich, moisture retentive, well-drained soil in sun or semi-shade[]. They grow well along the woodland edge or amongst large shrubs[]. They succeed in heavy clay soils. Plants can be grown in quite coarse grass, which can be cut annually in the autumn[].
Plants in this genus seem to be immune to the predations of rabbits[].
Hybridizes freely with other members of this genus[].

Edible Uses

Leaf stem - raw or cooked[, , , ]. An excellent flavour that is something like apples[, ] (this is likely to be a cooking apple!). The crop is sometimes blanched by excluding light from the growing stems, this produces an almost white stem that is free of fibre, crisp and less acid[]. This species makes an excellent late crop[]. The stems can also be made into a pickle or a preserve, and can be dried and stored for later use[, ].

One report says that the plant contains 0.32% rutin[]. It does not specify which part of the plant, though it is likely to be the leaves[].

Medicinal

Rhubarb has a long and proven history of herbal usage, its main effect being a positive and balancing effect upon the whole digestive system. It is one of the most widely used herbs in Chinese medicine[]. The main species used is Rheum palmatum, though several other species can be used. Although the chemistry varies slightly, Rheum australe is used interchangeably with Rheum palmatum[]. The plant is not advised as an internal treatment for patients suffering from gout, rheumatism or epilepsy[].

The root is anticholesterolemic, antiseptic, antispasmodic, antitumor, aperient, astringent, cholagogue, demulcent, diuretic, laxative, purgative, stomachic and tonic[, , , , , , , ]. The roots contain tannins and, when taken in small doses acts as an astringent tonic to the digestive system, relieving diarrhoea. At larger doses, however, the anthraquinones in the root exert their influence as a mild laxative and are a gentle treatment for constipation[, ]. The root is taken internally in the treatment of chronic constipation, diarrhoea, liver and gall bladder complaints, blood disorders, haemorrhoids, menstrual problems, sore throats and skin eruptions due to an accumulation of toxins[, ]. When taken internally, the root imparts a deep tinge to the urine[].
Applied externally, the root is used in the treatment of burns[]. A paste of the rootstock is used in treating scabies and other skin diseases[]. Combined with other herbs, the paste is applied to fix fractured bones, swellings, sprains etc[].
This remedy is not prescribed for pregnant or lactating women, nor for patients with intestinal obstruction[].
The roots are harvested at the end of the growing season from mature plants that are at least six years old, they are then dried for later use[, ].

A decoction or juice of the petioles is used as a diuretic and anthelmintic[].
The petioles are also chewed raw to treat intestinal worms and in gastritis and swellings[].
The young petioles and leaves are used to cure cuts and wound, sprains, and bodyache[].

A homeopathic remedy is prepared from the dried root[]. This is used especially in the treatment of diarrhoea in teething children[].

Other Uses

The leaves can be up to 1 metre in diameter, they are used as a lining material and also to cover and protect fruit in baskets[, ].

A bright yellow dye is obtained from the root[]. The rootstock yields a dye used for colouring wool[].
The petioles are used as a mordant[].

Propagation

Seed - best sown in autumn in a shaded cold frame[]. The seed can also be sown in spring in a cold frame. When large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse or cold frame for their first winter, planting them out in the spring.
Division in early spring or autumn[, ]. Divide up the rootstock with a sharp spade or knife, making sure that there is at least one growth bud on each division. Larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.