Rheum palmatum
Common Name: Chinese Rhubarb.
Family: Polygonaceae.
Known Hazards: The leaves are poisonous. This report probably refers to high levels of oxalic acid found in the leaves. Perfectly safe in moderate quantities, oxalic acid can lock up certain minerals (especially calcium) in the body, leading to nutritional deficiency. Cooking the plant will reduce its content 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.
Habitats: Scrub and rocky places and by streams, 2500 - 4000 metres. Slopes and valleys at elevations of 1500 - 4400 metres in western and northern China.
Range: E. Asia - N.W. China in Yunnan, W. Sichuan, E. Xizang and Gansu.
Physical Characteristics
Rheum palmatum is a PERENNIAL growing to 3 m (9ft) by 2 m (6ft). It is hardy to zone 7. It is in flower from Jun to July, and the seeds ripen from Jul to September. The flowers are hermaphrodite (have both male and female organs) and are pollinated by wind. The plant prefers medium (loamy) and heavy (clay) soils, requires well-drained soil and can grow in heavy clay soil. The plant prefers acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It requires moist soil.
Edible Uses
Leaf stem - raw or cooked. The stem is superior in flavour to the common rhubarb and quite tender. An acid flavour, it is sometimes used as a cooked fruit substitute.
Medicinal Uses
Plants For A Future cannot take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.
Medicinal Actions: Purgative; Stomachic; Tonic. Anticholesterolemic; Antiseptic; Antispasmodic; Antitumor; Aperient; Astringent; Cholagogue; Demulcent; Diuretic; Homeopathy; Laxative;
Chinese rhubarb, called Da Huang in China, 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. It has a safe and gentle action, safe even for children to use. The plant is also part of a North American formula called essiac which is a popular treatment for cancer. Its effectiveness has never been reliably proven or disproven since controlled studies have not been carried out.
The other herbs included in the formula are Arctium lappa, Ulmus rubra and Rumex acetosella. The root is anticholesterolemic, antiseptic, antispasmodic, antitumor, aperient, astringent, cholagogue, demulcent, diuretic, laxative, purgative, stomachic and tonic. The roots contain anthraquinones, which have a purgative effect, and also tannins and bitters, which have an opposite astringent effect. When taken in small doses, it acts 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, or 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.
Other Uses
An insect spray is made from the leaves. This spray is also said to help prevent clubroot of brassicas. The cultivar ‘Atrosanguineum’ can be used as a ground cover plant in a sunny position. Other forms can also be used, they are best planted about 1.8 metres apart each way.
Cultivation
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 at least -15°c. A very ornamental plant, there is at least one named variety.
Hybridizes freely with other members of this genus. The sub-species R. palmatum tanguticum is cultivated as a medicinal plant in China, it was at one time a popular purgative in Europe. Plants in this genus seem to be immune to the predations of rabbits. Turkish rhubarb is a good companion plant for columbine (Aquilegia spp).
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.
References available from source website.
