Rhubarb Background

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The Rhubarb Compendium
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1 - Botanical Information

Rhubarb, Pieplant. Polygonaceae (Buckwheat family) Rheum rhabarbarum (and other species).

1.1 - What is Rhubarb?

Rhubarb is a plant name for the many different species of Rheum, growing in the wild in the mountains of the Western and North-western provinces of China and in the adjoining Tibetan territory and in cultivation in much of Europe and the United States. 1 From Webster’s dictionary - rhuÀbarb, Pronunciation: ‘r³-”b?rb, noun, from Middle English rubarbe, from Middle French reubarbe, from Medieval Latin reubarbarum, alteration of rha barbarum, literally, barbarian rhubarb, 15th century.

Any of a genus (Rheum) of Asian plants of the buckwheat family having large leaves with thick succulent petioles often used as food- The dried rhizome and roots of any of several rhubarbs grown in China and Tibet and used as a purgative and stomachic- A heated dispute or controversy.

Rhubarb is a vegetable with a unique taste that makes it a favorite in many pies and desserts. It originated in Asia over 2,000 years ago. It was initially cultivated for its medicinal qualities, it was not until the 18th century that rhubarb was grown for culinary purposes in Britain and America. Rhubarb is often commonly mistaken to be a fruit but rhubarb is actually a close relative of garden sorrel, and is therefore a member of the vegetable family. Rhubarb is rich in vitamin C and dietary fiber. 2 3 4

Rhubarb is a perennial plant (the kind that grows from year to year) which forms large fleshy rhizomes and large leaves with long, thick (and tasty) petioles (stalks). Rhubarb stalks are commonly found in supermarkets, fresh rhubarb is prized by gourmet cooks. Some folks say the finest quality rhubarb is grown in Michigan, Ontario, Canada, and other northern states in the United States. Fresh rhubarb is available from early winter through early summer. Winter rhubarb is commercially produced in forcing houses in Michigan and Ontario. 5


Parts of a Rhubarb Plant
Figure 1.1: Parts of a Rhubarb Plant

1.2 - What are the different species of rhubarb?

There are many species of plants called rhubarb. The Rhubarb Compendium is primarily concerned with common garden rhubarb, Rheum x cultorum. Here is a list of common (and some not so common) rhubarbs.

Table 1.1: Rhubarb Species

Botanical Name	Common name	Description
Rheum acuminatum	Ornamental Rhubarb	This plant likes to grow in or near water, in summer it has red seedpods. It is disease-free and hardy all across the country (Canada). Low mounds of heavily veined leaves, rich red petioles, and upright, branched and spidery stems or red flowers to 4 feet (1.25 m). Adaptive to full sun or partial shade in rather rich, humusy soil. Cut it hard back after flowering to rejuvenate foliage for the remaining season. Excellent autumn tones of red in full sun.
Rheum alexandrae	Ornamental Rhubarb	An ornamental rhubarb. Spikes of flowers rising to 3-4 feet (1-1.25 m) completely shielded by large, translucent white bracts, and in autumn, spectacular red autumn color.
Rheum alpinum	European Wild Rhubarb	Leaves used for wrapping cheeses, rhizomes used as pig food.
Rheum altaicum
Rheum australe	Himalayan rhubarb	Seven foot (2 meter) long stems have yellow flowers in late spring-summer. Red stems with large greenish red, heart-shaped leaves.
Rheum compactum		Perennial, typical height 50 cm (19 in) Edible parts are the Leaf stems as a rhubarb substitute.
Rheum coreanum		Perennial, The root is laxative and is also considered good for digestion.
Rheum emodi		Rheum officinale and Rheum Emodi have to some extent been grown also as an ornamental plant, being also quite hardy and readily propagated.
Rheum kialense		A charming, diminutive species. Red-stained crinkled foliage to 15 inches (38 cm) and airy panicles of tiny greenish-red flowers. Stoloniferous (a stolon is a horizontal branch from the base of a plant that produces new plants from buds at its tip or nodes (like a strawberry does), also called a runner), it will form a dense groundcover over time.
Rheum nobile	Sikkim rhubarb
Rheum officinale	Chinese rhubarb Indian rhubarb	Perennial, typical height 2 m ( 6.5 ft) E. Asia - Tibet. Hardy to USDA Zone 7. Leaf stem eaten cooked or raw, Rhizome considered medicinal.
Rheum palmatum	Turkey rhubarb Chinese rhubarb East Indian Rhubarb	Some sources say Rheum palmatum is a synonym for Rheum rhaponticum but this is not correct. The leaves of the Turkey Rhubarb are palmate and somewhat rough. The root is thick, of an oval shape, sending off long, tapering branches; externally it is brown, internally a deep yellow color. The stem is erect, round, hollow, jointed, branched towards the top, from 6 to 10 feet (2-3 m) high. This species is distinguished from our familiar garden Rhubarb by its much larger size, the shape of its leaves, with their oblong, sharpish segments, and the graceful looseness of its little panicles of greenish-white flowers. The first buds which appear in spring are yellow, not red. Perennial, typical height 2 m (6.5 ft), Leaf stem eaten raw or cooked. Superior in flavor to the common rhubarb and quite tender, has a long and proven history of herbal/medicinal usage Bold, dramatic dark purple foliage with 6 foot (2 m) long stems that bear rose-red pyramids of flowers in late spring. Several varieties of this are known: ‘Atrosanguineum’, ‘Bowles Crimson’, rubrum, tanguticum, and tanguticum ‘red selection’.
Rheum rhaponticum Rheum x hybridum Rheum rhabarbarum Rheum x cultorum	Rhubarb Garden Rhubarb Bastard Rhubarb Sweet Round-leaved Dock English Rhubarb Wine Plant	R051.jpg (14587 bytes)Strong perennial, with thick clustered roots. Similar in medicinal action to Turkey Rhubarb or Chinese Rhubarb, though milder. It is derived from Rheum palmatum, and from Rheum officinale. It has blunt, smooth leaves; large, thick roots, running deep into the ground, reddish-brown outside and yellow within, and stems 2 to 3 feet high, jointed and purplish. The flowers are white.
Rheum ribes		Perennial, typical height 1.5 m. ( 4.9ft.) Leaf stem - cooked. Eaten raw by the people of Turkey and Iraq.
Rheum spiciforme		Perennial, typical height 30 cm. (11 in.) E. Asia - Himalayas. Leaf stem - raw or cooked. The root is used as a purgative.
Rheum tataricum	Tartarian rhubarb
Rheum tibeticum
Rheum undulatum		4-5 feet (1.25-1.5 m) tall, Earlier and smaller than R. rhaponticum

Table references: 6 7 8 9 10 11 12

1.3 - What plants are called rhubarb but really are not?

A few plants are called rhubarb or have names that somehow relate them to rhubarb, usually because they look like rhubarb.

Table 1.2: Things that are not really Rhubarb

Botanical Name	Common name	Description
Beta vulgaris	Spinach rhubarb	R050.jpg (17898 bytes)Not a rhubarb but has rhubarb like leaf stems (thick and bright red).
Rumex alpinus	Monk’s Rhubarb Garden Patience	Monk’s Rhubarb is a Dock bearing the name of Rhubarb for some purging quality. The root-stock is very stout, yellow color; the stem 2 to 4 feet (60-120 cm) high, bearing pale green leaves, broad and very long, the edges waved, but not cut into. The tops of the stems are divided into many small branches, bearing reddish or purple flowers, succeeded by angular seeds, as in other docks. The medicinal virtues of the root, when dried, are similar to the Garden Rhubarb, but are not so strong.
Rumex hymenosepalus	Wild Rhubarb Red Dock Desert Ginseng	Indians used the roots to soften their buckskins since it contains tannin. The root was used to make tea for treating diarrhea and as a gargle for easing sore throat. The plant was also used as a source of dye (yellow hue in dyeing wool - stalks are an excellent substitute for rhubarb. This plant is a native of Western US. The bitter succulent leaves were roasted on hot ash beds. (Young leaves of some species are more edible, and even used to be cultivated as a vegetable in Europe.
Gunnera manicata	Giant Rhubarb Giant Gunnera	gunnera.jpg (13043 bytes)Huge plant, mammoth, wrinkly, dark green leaves to 9 feet (3 meters) across on stout prickly stems grow from a pink, fuzzy, watermelon-sized crown. Creates a bold, tropical look for sheltered, damp spots. Large cone-shaped flowers, 5 inches (13 cm) across at the base and 2-3 feet (1 m) tall, change from green through red, and brown. Needs a covering of bracken. Magnificent in summer. Ideal for lakes, large ponds, damp ditches, etc. A very conspicuous plant for the pond-side or boggy spot.
Reynoutria japonica	Japanese Knotweed Donkey Rhubarb	Forms thickets of stout, rather zig-zag, red-brown stems up to nearly 6 feet (2 m) high, with broad pointed leaves straight at the base. Flowers white and feathery. Many of us know it as Donkey Rhubarb - presumably because one would be a donkey to attempt to eat these rhubarb-like stems. Also known as Polygonum cuspidatum. A very aggressive invader of disturbed and shaded habitats.
Darmera peltata	Indian Rhubarb umbrella plant Saxifraga peltata Peltiphyllum peltatum	darmera.jpgLeafless, early spring stems of rich pink flowers emerge from the damp soil to 2 feet (0.6 meter), to be replaced later by enormous, umbrella-like leaves that color richly in autumn if grown in full sun. An outstanding American native. Will tolerate some periods of standing water. Pink flowers emerge in spring, replaced by large round leaves later. For moist soil. USDA Zone 6.
Petasites japonicus	Petasites hybridus Butterbur Bog Rhubarb Plague Flower Langwort Flapperdock Blatterdock Capdockin Bogshorns Butter-Dock	It has a fleshy, stout root-stock, extensively creeping, which, like the Coltsfoot, sends up the flowers before the leaves appear. The flower-heads are, however, not produced singly, on separate stalks, but in crowned clusters in a dense spike, with many bracts interspersed, at the summit of a round, thick flower-stalk, 4 inches (10 cm) to a little over 1 foot (30 cm) in height, which first appears in late winter or very early spring, and is generally of a purplish hue. Leaves formerly used as rain hats and for wrapping butter; contains toxic alkaloids; used externally in herbalism; flowers used in an attempt to cure bubonic plague.

Table references: 13 14 15 16

Rhubarb leaves grow from the ground in early spring (see Growing Rhubarb). The leaves can grow up to a foot or more in width and length and the plant may grow to a height of several feet. The blade or green leaves of the plant are the part that is poisonous. They contain high concentrations of oxalic acid crystals which can cause serious problems when eaten. These crystals can cause the tongue and throat to swell, preventing breathing (see Health Information). The edible petioles (stalks) are up to 18 inches long, 1 to 2 inches in diameter, generally somewhat hemispherical in cross section. These petioles are cut and used in pies, jams, jellies, sauces and juice. Rhubarb rhizomes and the crown persist for many years. The roots are also taken up and bedded in cellars or houses in winter, forcing growth in darkness to produce etiolated leaf-stems, which are much prized (see Forcing Rhubarb). 17 18 19 20 21

Readers of The Rhubarb Compendium may be interested in…

Botany for Gardeners: An Introduction and Guide

Brian Capon

How do plants grow? What exactly is photosynthesis? How did plants evolve and how do they adapt to environmental stress? What does each part of a flower do? How do plants reproduce and pass on their genes? This highly readable introduction to how plants work answers all these questions and more, always looking at botany from a gardener’s point of view. Capon explains the structure and function of plants in clear, understandable language, including and defining all the relevant scientific terms. The book introduces readers to cell structure and function, plant growth processes, the many ways plants adapt to protect themselves from predators and the environment, and how plants meet their basic needs for food and water. Photosynthesis, reproduction, and the aging process are explained, and the fascinating processes necessary for the transmission of genes are discussed in detail. Excellent color photos, line drawings, and diagrams accompany the lucid text. Botany for Gardeners never ceases to receive fan mail from grateful plant lovers who now look at plants in a whole new way. [b01]

Footnotes:

Rhubarb, http://newcrop.hort.purdue.edu/hort/newcrops/Crops/Rhubarb, (from New Crop Resource Online Program, Indiana Center for New Crops and Plant Products)- 03900106 (Growing Rhubarb), http://lep.cl.msu.edu/msueimp/htdoc/mod03/03900106.html (from “Rhubarb: Cultural Guidelines for Michigan” by Diana Helsel, Dale Marshall and Bernard Zandstra Cooperative Extension Service, Michigan State University)- Rhubarb, http://aggie-horticulture.tamu.edu/plantanswers/vegetables/rhubarb.html, (from Aggie Horticulture, Texas Horticulture Program)- Rhubarb, http://www.veg.org/veg/Orgs/VegSocUK/Recipes/rhubarb2.html, (from “The Vegetarian Spring 1995”, The Vegetarian Society UK, Moved to: http://www.vegsoc.org/)- Rhubarb, http://aggie-horticulture.tamu.edu/plantanswers/vegetables/rhubarb.html, (from Aggie Horticulture, Texas Horticulture Program)- Rhubarbs, http://www.botanical.com/botanical/mgmh/r/rhubar14.html, (from Botanical.com)- Untitled page, part of The Plant Tracker- Guide to Plant Relationships (for food allergy and intolerance identification), http://www.purr.demon.co.uk/Food/RelatedPlantList.html- Willow Pond Nursery, URL: http://www.willowpondnursery.com/index.htm- Heronswood Nursery, http://www.heronswood.com/- Bailey- Japanese Knotweed (Reynoutria japonica), http://www.ex.ac.uk/~cnfrench/ics/cbru/monitor/reyjap.htm, (from The Cornish Biological Records Unit)- Rhubarbs, http://www.botanical.com/botanical/mgmh/r/rhubar14.html, (from Botanical.com)- Guide to Plant Relationships (for food allergy and intolerance identification), http://www.purr.demon.co.uk/Food/RelatedPlantList.html- Heronswood Nursery, http://www.heronswood.com/- Japanese Knotweed (Reynoutria japonica), http://www.ex.ac.uk/~cnfrench/ics/cbru/monitor/reyjap.htm, (from The Cornish Biological Records Unit)- Veggies Unit: your on-line guide to vegetarianism, http://www.honors.indiana.edu:80/~veggie/recipes.cgi/, (The University of Illinois, College of Agricultural, Consumer and Environmental Sciences, Foods and Nutrition Solutions Series)- 03900106 (Growing Rhubarb), http://lep.cl.msu.edu/msueimp/htdoc/mod03/03900106.html (from “Rhubarb: Cultural Guidelines for Michigan” by Diana Helsel, Dale Marshall and Bernard Zandstra Cooperative Extension Service, Michigan State University)- Rhubarb (a description), http://www.ag.uiuc.edu/~robsond/solutions/horticulture/docs/rhubarb1.html, (from the Illinois Cooperative Extension Service Horticulture Solution Series )- Rhubarb, http://aggie-horticulture.tamu.edu/plantanswers/vegetables/rhubarb.html, (from Aggie Horticulture, Texas Horticulture Program)- Rhubarb, http://newcrop.hort.purdue.edu/hort/newcrops/Crops/Rhubarb, (from New Crop Resource Online Program, Indiana Center for New Crops and Plant Products)

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Updated on September 1, 2004
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