Himalayan Rhubarb
Rheum australe

Family: Polygonaceae

What it is like

Rheum australe is a PERENNIAL growing to 3 m (9ft) by 1.5 m (5ft). See above for USDA hardiness. It is hardy to UK zone 6. It is in flower from June to July, and the seeds ripen from July to August. The species is hermaphrodite (has both male and female organs) and is pollinated by Wind. Suitable for: medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in heavy clay soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 3

Where it is found

Open slopes on rocky ground at elvations of 3200 - 4200 metres. Grassy slopes at elevations of 3400 - 4300 metres in Tibet.

E. Asia - Himalayas.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 3

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 preserve or 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.

Stem: this often intergrades into leaves.

Rutin: often used as a food supplement.

Medicine

Rating: 3

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 R. palmatum. Though the chemistry varies slightly, this species is used interchangeably. The root is anticholesterolemic, antiseptic, antispasmodic, antitumor, aperient, astringent, cholagogue, demulcent, diuretic, laxative, purgative, stomachic and tonic. Small doses act as an astringent tonic to the digestive system, whilst larger doses act as a mild laxative. The root is taken internally in the treatment of chronic constipation, diarrhoea, liver and gall bladder complaints, haemorrhoids, menstrual problems and skin eruptions due to an accumulation of toxins. This remedy is not prescribed for pregnant or lactating women, nor for patients with intestinal obstruction. Externally, the root is used in the treatment of burns. The roots are harvested in October from plants that are at least six years old, they are then dried for later use. A homeopathic remedy is prepared from the dried root. This is used especially in the treatment of diarrhoea in teething children.

Digestive: Aids digestion.

Purgative: A drastic laxative causing a cleansing or watery evacuation of the bowels, usually with a griping pain.

Tonic: Improves general health. Slower acting than a stimulant, it brings steady improvement.

Other

Rating: 2

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.

Dye: Plants that provide dyes.

Lining: Used for lining boxes, baskets etc so that fragile items can be more safely carried in them.

Food Forest: Plants for Edible Forest Gardens and Food Forests.

How it is grown

Prefers a deep, fertile, moderately heavy, humus rich, moisture retentive, well-drained soil in sun or semi-shade. Grows well in heavy clay soils. Plants can be grown in quite coarse grass, which can be cut annually in the autumn. Hardy to about -20°c. Plants in this genus seem to be immune to the predations of rabbits. Hybridizes freely with other members of this genus. The root is sold for medicinal purposes in local markets in the Himalayas. Overgathering of this plant from the wild, both for food and for medicine, is becoming a cause of conservation concern. The plant is heat tolerant in zones 8 through 5. (Plant Hardiness Zones show how well plants withstand cold winter temperatures. Plant Heat Zones show when plants would start suffering from the heat. The Plant Heat Zone map is based on the number of "heat days" experienced in a given area where the temperature climbs to over 86 degrees F (30°C). At this temperature, many plants begin to suffer physiological damage. Heat Zones range from 1 (no heat days) to 12 (210 or more heat days). For example Heat Zone. 11-1 indicates that the plant is heat tolerant in zones 11 through 1.) For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. The plant growth habit is a clumper with limited spread.

Propagating it: 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.

Best place to grow: Cultivated Beds;

Habit: Perennial

Hardiness: 5-9

Growth:

Soil: Medium, heavy (clay)

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

Although no specific mention has been seen for this species, the leaves of some if not all members of this genus contain significant quantities of oxalic acid and should not be eaten in any quantity. Oxalic acid can lock up certain minerals in the body, especially calcium, leading to nutritional deficiency. The content of oxalic acid will be reduced if the plant is cooked. 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.

Its other names

Local names

Synonyms

R. emodi. Wall.