Common Name: Sikkim Rhubarb

General Information

Rheum nobile is a herbaceous perennial plant growing from a stout, woody, rhizomatous rootstock; it produces a basal clump of leaves around 20 - 30cm in diameter on stout petioles that are around 5 - 20cm long; the plant flowers in the summer, producing stout, unbranched flowering stems around 100 - 200cm tall[, ].
The plant is harvested from the wild for local use as a food and medicine. It is sold for medicinal use in local markets according to one report[], though another says that the roots resemble those of Rheum australe, but are spongy and inert[]. It is grown as an ornamental, valued especially for its large flowering spikes[].

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 - Himalayan regions of Afghanistan, Pakistan, northern India, Nepal, Tibet and northern Myanmar

Habitat

Rock ledges; at elevations around 4,000 metres[]. Open alpine grassy and rocky slopes, morainic deposits; at elevations around 3,600 - 5,000 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Perennial
Height	1.50 m
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Rheum nobile 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 have proved very difficult to grow in cultivation in Britain[].
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[, , , ]. Used to make pickles[]. Pleasantly acid, this is a commonly used vegetable where it grows wild[, ].

The young flowering stem is cooked and eaten as a vegetable[].

Medicinal

One report says that the roots resemble those of Rheum emodi, but are spongy and inert[]. Other reports, below, say that the plant is commonly used for medicinal purposes..

The root is astringent, carminative, depurative, diuretic, purgative and tonic[, , ]. Small doses act as an astringent tonic to the digestive system, whilst larger doses act as a mild laxative[]. A decoction is used in the treatment of stomach and menstrual disorders[]. The root extract is also taken orally in cases of fracture and body pain[].
The rootstocks used to make poultices to treat fractures. The rootstocks are boiled and made into a paste with a little flour along with traces of Tibetan salt, and the paste is applied to the fracture area[]. Combined with the rhizome of Bergenia ciliata, the roots are boiled then made into a paste that is applied externally in the treatment of bone fractures[].

The flowering stem is used in Tibetan medicine, it is said to have a sour taste and a heating potency[]. It is antiemetic, diuretic and laxative[]. It is used in the treatment of swellings and fullness of the abdomen as well as to rid the body of retained fluids[].

Other Uses

None known

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.