Rhubarb (Rheum rhabarbarum) is a species of plant in the family
Polygonaceae. It is a herbaceous perennial growing from short, thick
rhizomes. It produces large leaves which contain oxalic acid, are
somewhat triangular, with long fleshy edible stalks and small flowers
grouped in large compound leafy greenish-white to rose-red
In culinary use, fresh raw leaf stalks (petioles) are crisp (similar
to celery, although they do not share the same family) with a strong,
tart taste. Although rhubarb is not a true fruit, in the kitchen it is
usually prepared as if it were. Most commonly, the stalks are
cooked with sugar and used in pies, crumbles and other desserts. A
number of varieties have been domesticated for human consumption, most
of which are recognised as Rheum x hybridum by the Royal Horticultural
Rhubarb contains anthraquinones including rhein, and emodin and their
glycosides (e.g. glucorhein), which impart cathartic and laxative
properties. It is hence useful as a cathartic in case of
1.1 Historical cultivation
2.2 Folk medicine
7 Further reading
8 External links
Rhubarb displayed for sale at a market in Leeds, England
Rhubarb is grown widely, and with greenhouse production it is
available throughout much of the year.
Rhubarb grown in hothouses
(heated greenhouses) is called "hothouse rhubarb", and is typically
made available at consumer markets in early spring, before outdoor
cultivated rhubarb is available. Hothouse rhubarb is usually brighter
red, more tender and sweeter-tasting than outdoor rhubarb. In
temperate climates, rhubarb is one of the first food plants harvested,
usually in mid- to late spring (April/May in the Northern Hemisphere,
October/November in the Southern Hemisphere), and the season for
field-grown plants lasts until September. In the northwestern US
states of Oregon and Washington, there are typically two harvests,
from late April to May and from late June into July.[citation
Rhubarb is ready to consume as soon as harvested, and freshly
cut stalks are firm and glossy.
In the United Kingdom, the first rhubarb of the year is harvested by
candlelight in forcing sheds where all other light is excluded, a
practice that produces a sweeter, more tender stalk. These sheds
are dotted around the "
Rhubarb Triangle" between Wakefield, Leeds, and
The advocate of organic gardening
Lawrence D. Hills listed his
favorite rhubarb varieties for flavor as Hawke's Champagne, Victoria,
Timperley Early, and Early Albert, also recommending Gaskin's
Perpetual for having the lowest level of oxalic acid, allowing it to
be harvested over a much longer period of the growing season without
developing excessive sourness.
Because rhubarb is a seasonal plant, obtaining fresh rhubarb out of
season is difficult in colder climates, such as in the UK, Ireland,
Rhubarb thrives in areas of direct sunlight and can
successfully be planted in containers if they are large enough to
accommodate a season's growth.
Rhubarb damaged by severe cold should not be eaten, as it may be high
in oxalic acid, which migrates from the leaves and can cause
A bundle of rhubarb
The color of rhubarb stalks can vary from the commonly associated
crimson red, through speckled light pink, to simply light green.
Rhubarb stalks are poetically described as "crimson stalks". The color
results from the presence of anthocyanins, and varies according to
both rhubarb variety and production technique. The color is not
related to its suitability for cooking: The green-stalked rhubarb
is more robust and has a higher yield, but the red-coloured stalks are
much more popular with consumers.
The Chinese call rhubarb "the great yellow" (dà huáng 大黃), and
have used rhubarb root for medicinal purposes for thousands of
years. It appears in The Divine Farmer's Herb-Root Classic which is
thought to have been compiled about 2,700 years ago. Though
Dioscurides' description of ρηον or ρά indicates that a
medicinal root brought to Greece from beyond the
Bosphorus may have
been rhubarb, commerce in the drug did not become securely established
until Islamic times. During Islamic times, it was imported along the
Silk Road, reaching Europe in the 14th century through the ports of
Aleppo and Smyrna, where it became known as "Turkish rhubarb".
Later, it also started arriving via the new maritime routes, or
overland through Russia. The "Russian rhubarb" was the most valued,
probably because of the rhubarb-specific quality control system
maintained by the Russian Empire.
The cost of transportation across Asia made rhubarb expensive in
medieval Europe. It was several times the price of other valuable
herbs and spices such as cinnamon, opium, and saffron. The merchant
Marco Polo therefore searched for the place where the plant
was grown and harvested, discovering that it was cultivated in the
mountains of Tangut province. The value of rhubarb can be seen in
Ruy Gonzáles de Clavijo's report of his embassy in 1403–05 to Timur
in Samarkand: "The best of all merchandise coming to
from China: especially silks, satins, musk, rubies, diamonds, pearls,
The high price as well as the increasing demand from apothecaries
stimulated efforts to cultivate the plant on European soil. These were
unsuccessful in producing rhubarb root with the necessary medicinal
qualities, but the variety then grown in
Russia became the ancestor of
the common modern rhubarb. The availability of this "Siberian
rhubarb", together with the increasing abundance and decreasing price
of sugar in the 18th century, galvanised its culinary adoption.
The term "rhubarb" is a combination of the
Ancient Greek rha and
barbarum; rha refers both to the plant and to the River Volga. For
centuries, the plant has grown wild along the banks of the River
Volga, for which the ancient Scythian hydronym was Rhā.
Though it is often asserted that rhubarb first came to the United
States in the 1820s,
John Bartram was growing medicinal and
culinary rhubarbs in Philadelphia from the 1730s, planting seeds sent
him by Peter Collinson. From the first, the familiar garden
rhubarb was not the only Rheum in American gardens: Thomas Jefferson
planted R. undulatum at Monticello in 1809 and 1811, observing that it
was "Esculent rhubarb, the leaves excellent as Spinach."
Dried strawberry-flavoured rhubarb
Rhubarb is grown primarily for its fleshy stalks, technically known as
petioles. The use of rhubarb stalks as food is a relatively recent
innovation. This usage was first recorded in 17th-century England
after affordable sugar became available to common people, and reached
a peak between the 20th century's two world wars.
Commonly, it is stewed with sugar or used in pies and desserts, but it
can also be put into savory dishes or pickled.
Rhubarb can be
dehydrated and infused with fruit juice. In most cases, it is infused
with strawberry juice to mimic the popular strawberry rhubarb pie.
Rhubarb root produces a rich brown dye similar to walnut husks. It is
used in northern regions where walnut trees do not survive.
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A homemade rhubarb pie
For cooking, the stalks are often cut into small pieces and stewed
(boiled in water) with added sugar, until soft. Little water is added,
as rhubarb stalks already contain a great deal of water. Rhubarb
should be processed and stored in containers which are unaffected by
residual acid content, such as glass or stainless steel. Spices such
as cinnamon, nutmeg, and ginger are sometimes added. Stewed rhubarb or
rhubarb sauce, like applesauce, is usually eaten cold. Pectin, or
sugar with pectin, can be added to the mixture to make jams.
A similar preparation, thickened with cornstarch or flour, is used as
filling for rhubarb pie, tarts, and crumbles, leading to the nickname
"pie plant", by which it is referred to in many 19th-century
cookbooks, as well as by American author Laura Ingalls Wilder in
her short novel The First Four Years. The term "pie plant" is still
used regionally in the U.S.
In recent times rhubarb has often been paired with strawberries to
make strawberry-rhubarb pie, though some rhubarb purists jokingly
consider this "a rather unhappy marriage".
In former days, a common and affordable sweet for children in parts of
United Kingdom and
Sweden was a tender stick of rhubarb, dipped in
sugar. It is still eaten this way in western Finland, Norway, Iceland
and Sweden, and also some other parts of the world. In Chile, Chilean
rhubarb, which is only very distantly related, is sold on the street
with salt or dried chili pepper, not sugar.
Rhubarb can be used to make a fruit wine or sima. It is also used to
make compote. Being a bit sour, it is very refreshing and can be
drunk cold, especially during the summer.
In traditional Chinese medicine, rhubarb roots have been thought of as
a laxative for several millennia.
Rhubarb also appears in medieval
Arabic and European prescriptions. It was one of the first
Chinese medicines to be imported to the West from China.
The roots and stems are rich in anthraquinones, such as emodin and
rhein. These substances are cathartic and laxative, explaining the
sporadic use of rhubarb as a dieting aid. The anthraquinone compounds
have been separated from powdered rhubarb root for medicinal
The rhizomes contain stilbenoid compounds (including rhaponticin),
which seem to lower blood glucose levels in diabetic mice.
Rhubarb also contains the flavanol glucosides
(+)-catechin-5-O-glucoside and (−)-catechin-7-O-glucoside.
Rhubarb contains carbon-based quinone molecules which are capable of
carrying an electrical charge. In 2014, a Harvard-based team of
scientists published results describing the use of the quinone
AQDS, almost identical to a form found in rhubarb, in
Young rhubarb flowers
Rhubarb leaves contain poisonous substances, including oxalic acid,
which is a nephrotoxic and corrosive acid that is present in many
plants. Humans have been poisoned after ingesting the leaves, a
particular problem during
World War I
World War I when the leaves were mistakenly
recommended as a food source in Britain. The toxic rhubarb
leaves have been used in flavoring extracts, after the oxalic acid is
removed by treatment with precipitated chalk (i.e., calcium
Oxalic acid can also be found in the stalks of rhubarb,
but the levels are too low to cause any bodily harm.
The LD50 (median lethal dose) for pure oxalic acid in rats is about
375 mg/kg body weight, or about 25 grams for a 65-kilogram
(143 lb) human. Other sources give a much higher oral LDLo
(lowest published lethal dose) of 600 mg/kg. While the oxalic
acid content of rhubarb leaves can vary, a typical value is about
0.5%, so a rather unlikely 5 kg (for a 70 kg human) of
the extremely sour leaves would have to be consumed to reach the LD50
of oxalic acid.[original research?] Cooking the leaves with baking
soda can make them more poisonous by producing soluble oxalates.
However, the leaves are believed to also contain an additional,
unidentified toxin, which might be an anthraquinone glycoside
(also known as senna glycosides).
In the petioles (stalks), the proportion of oxalic acid is much lower,
only about 2–2.5% of the total acidity, which consists mostly of
The rhubarb curculio, Lixus concavus, is a weevil.
Rhubarb is a host,
damage being visible mainly on the leaves and stalks, with gummosis,
and oval or circular feeding and/or egg-laying sites.
Hungry wildlife may dig up and eat rhubarb roots in the spring, as
stored starches are turned to sugars for new foliage growth.
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Wikimedia Commons has media related to Rheum rhabarbarum.
Wikibooks Cookbook has a recipe/module on
Rhubarb at Curlie (based on DMOZ)
Herbs used as laxatives
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