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Polygonaceae, Part two: Knotgrasses and Knotweeds:

Two infamous plants with attractive white flowers: Bindweed and Japanese Knotweed!

Last week we talked about the more prominent genera and species of the Polygonaceae, this week about the other 9 remaining genera which also has one famous non native weed: the Japanese knotweed!

Please follow links for more information. Pictures by Matt Summers or from Wikipedia Commons. FBBC added behind name if the plants occur in the Birmingham and Black Country area.

Contents:

Persicaria spp. or Knotweeds

Koenigia spp.

Fagopyrum spp or Buckwheats (neophytes)

Polygonum spp. or Knotgrasses

Bistorta spp.

Fallopia spp or Rusian Vines

  • F. baldschuanica or Russian-vine (neophyte) FBBC
  • F. convolvulus or Black-bindweed (archaeophyte) FBBC
  • F. dumetorum or Copse-bindweed

Reynoutria spp. or Knotweeds

  • R. japonica or Japanese Knotweed (neophyte) FBBC
  • R. sachalinensis or Giant Knotweed (neophyte) FBBC
  • R. × ⁠bohemica (= R. japonica × sachalinensis) or Bohemian Knotweed FBBC

Muehlenbeckia complexa or Wireplant

Rheum spp. or Rhubarbs

  • R. palmatum or Ornamental Rhubarb
  • R.  × ⁠rhabarbarum or Rhubarb FBBC

Persicaria spp.

Persicaria is a genus of herbaceous flowering plants in the knotweed family, Polygonaceae, with more than 130 spp. Plants of the genus are known commonly as Knotweeds. It has a cosmopolitan distribution, with species occurring nearly worldwide. The genus was segregated from Polygonum. There are 10 species in the B.I. of which 4 are neophytes.

The Amphibious Bistort is an attractive floating plant! (picture by I, Svdmolen, Wikipedia Commons)

A floating aquatic perennial herb, which sometimes grows in considerable quantity in lakes, ponds, canals, slow-flowing rivers and ditches, or a terrestrial plant found in damp places on watersides, in marshes, wet meadows and dune-slacks, and as a weed of cultivated land. Reproduction is by seed and fragments of rhizome; terrestrial plants are much less floriferous than aquatic ones.

Uses:

Various parts of this plant were used by several Native American groups as medicinal remedies and sometimes as food.

P. capitata or Pink-headed Persicaria (By Meneerke bloem – Wikipedia Commons)

An often mat-forming glandular pubescent perennial herb, with weakly ascending, creeping or trailing stems sometimes rooting at the lower nodes and only half-hardy in Britain and Ireland (elsewhere it is naturalized in milder climates; Madeira and the Azores for example). It is widely grown in gardens, escapes sporadically and persists locally for short periods, especially at the bases of walls and in pavement cracks.

This is an attractive garden and groundcover plant. But between 2008 and 2013 it has been recorded as an invasive plant in Ireland from the Counties Fermanagh,  Kilkenny,  Wexford and Mayo.

Medicinal Uses:

Persicaria capitata has been widely used in China in the treatment of various urologic disorders including urinary calculi and urinary tract infections.

Persicaria hydropiper or Water pepper

P. hydropiper or Water-pepper

An annual herb of damp mud on the margins of ponds and lakes, canals, rivers and streams, or shallow depressions such as vehicle tracks and hoof-marks in woodland rides, around field gateways and in wet meadows and fens. It is almost invariably in sites which are waterlogged in winter, often on base-poor soils and sometimes in partial shade. 

Edible Uses:

  • Leaves and stems – raw or cooked. They can also be made into an acid peppery condiment. 
  •  Seed – raw or cooked. It is rather small and fiddly to utilize. The seed is used as a condiment – a pepper substitute
  • The sprouted seeds or young seedlings can be used as a garnish or added to salads, they are commonly sold in Japanese markets. They are very hot.

Medicinal uses:

  • Water-pepper (or Smartweed) has a long history of herbal use, both in Eastern and Western herbalism.  The leaves are anti-inflammatory, astringent, carminative, diaphoretic, diuretic, emmenagogue, stimulant, stomachic, styptic. They contain rutin, which helps strengthen fragile capillaries and thus helps prevent bleeding. Use with caution.
  • The seed is carminative, diuretic and stimulant. The whole plant, either on its own or mixed with other herbs, is decocted and used in the treatment of a wide range of ailments including diarrhoea, dyspepsia, itching skin, excessive menstrual bleeding and haemorrhoids
  •  A poultice of the plant is used in treating swollen and inflamed areas.
  • A homeopathic remedy is made from the leaves. It is used in the treatment of piles, menstrual pains and other menstrual complaints.

Other Uses:

A yellow-gold dye is obtained from the stalks.  

two toned Persicaria lapathifolia is attractive enough as a border plant?
P. maculosa or Redshank: Stem with ciliate ochrea (By Stefan.lefnaer – Wikipedia Commons)

An annual of open ground on a wide range of soils, particularly those which are rich in nutrients. It is found by ponds, lakes, streams and ditches, in waste places, in open wet woodland, on roadsides and railways, and is sometimes a weed of cultivated land. Morphologically variable, P. maculosa var. biformis and P. maculosa var. ruderalis have been noted for Britain, as has P. maculosa subsp. hirticaulis.

Persicaria maculosa contains persicarin and tannins. The young leaves may be eaten as a leaf vegetable. It is often seen as a weed and rarely cultivated. A yellow dye can be produced from this plant with alum used as a mordant.

Medicinal Uses:

Persicaria maculata and  P. lapathifolia are of similar use as  P. hydropiper but are acting a lot weaker, which makes it more appropriate for the skin and for the kidney and urinary passages.  P. lapathifolium has greater amounts of Vitamin C. too.

The native range of this species is Eritrea to KwaZulu-Natal, Madagascar, Tropical & Subtropical Asia to Russian Far East. It is an annual and grows primarily in the subtropical biome.

It is has environmental uses and social uses, as animal food and a medicine and for food.

There is also an ornamental form of this.

Native Americans have various uses for the plant. The Chippewa use it for epilepsy.  The Iroquois use it for horse colic. The Menominee take a leaf infusion for hemorrhage of blood from the mouth and post-partum healing. The Meskwaki use it on bleeding hemorrhoids.

Koenigia spp.

Stace list the following 6 species below which have changed there names from Persicaria to Koenigia. Many of those seem to be garden escapes.

  • Persicaria alpina => Koenigia alpina.
  • Persicaria x fennica => Koenigia x fennica.
  • Persicaria campanulata => Koenigia campanulata.
  • Persicaria weyrichii => Koenigia weyrichii.
  • Persicaria mollis => Koenigia mollis.
  • Persicaria wallichii => Koenigia polystachya.
Koenigia islandica or Iceland purslane (By Jacek Pietruszewski – Wikipedia Commons)

Koenigia islandica or Iceland purslane

A tiny annual herb of wet, gravelly flushes on basalt, stone polygons and screes, usually with a north or east aspect, and occasionally on south-facing slopes. The instability of these habitats is maintained by freeze-thaw cycles, salt-spray and wind exposure creating suitable conditions for annual growth and preventing colonization by more vigorous species.

K. mollis or Soft Knotweed (By Vinayaraj – Wikipedia Commons)

According to the RHS:

A semi-evergreen or herbaceous perennial with attractively veined, ovate leaves which are whitish, later pale brown, beneath, and short panicles of small, bell-shaped, pale pink flowers.

K. polystachya or Himalayan Knotweed in Belgium (By Gilles San Martin – Wikipedia Commons)

A tall, rhizomatous perennial herb, widely grown in gardens and found growing in dense stands on streamsides, hedgebanks, roadsides, railway banks and waste ground. Its flowers are heterostylous and seed is only occasionally set in Britain, but it establishes readily by vegetative reproduction from outcast rhizomes.

Called thothnay in Sikkim and Darjeeling areas of India, the pleasantly sour-tasting edible shoots and stems are used as vegetable or used to make piquant condiments and accompaniments for meals.

Fagopyrum spp or Buckwheats (neophytes)

This is a domesticated plant used in traditional Chinese medicine, for animal feed, and as an ornamental plant. It is native to much of China, and to Bhutan, Nepal, India, Burma, and Vietnam.

Young plants of Buckwheat from seed shedding after harvest: (Rasbak – Wikipedia Commons)

F. esculentum or Buckwheat

An annual crop plant appearing erratically on waste ground, refuse tips, field margins, in woodland rides, as a weed of gardens, allotments and pavements, and as a relic of cultivation. More rarely it has been recorded from damp grassland, riversides, and pond margins.

Buckwheat Uses:

Despite its name, buckwheat is not closely related to wheat. Buckwheat is not a cereal, nor is it even a member of the grass family. It is related to sorrel, knotweed, and rhubarb. Buckwheat is considered a pseudocereal, because its seeds’ high starch content allows them to be used in cooking like a cereal.

Lots of dishes are made with the Buckwheat. Some examples below:

Roasted Buckwheat (By Candrichuk – Wikipedia Commons)
Flour(By Rasbak – Wikipedia Commons) CC BY-SA 3.0,
Korean pancakes from buckwheat (By cube300 at Flickr )

It is cultivated for its grain-like seeds and as a cover crop. Cover crops can

  • prevent soil erosion.
  • grows well in low-fertility or acidic soils
  • sometimes used as a green manure, or as wildlife cover and feed.

A multitude of Uses by PFAF:

Edible Uses:

Leaves can be eaten raw or cooked. Acceptable raw when added in small quantities to mixed chopped salads, otherwise the leaves are much better cooked[K]. They are rich in rutin. Seed – cooked as a cereal. The seed can also be sprouted and used in salads, or ground into a powder and used as a cereal. An edible oil is obtained from the seed.

Polygonum spp. or Knotgrasses:

Polygonum is a genus of about 130 species and primarily grows in northern temperate regions. The species are very diverse, ranging from prostrate herbaceous annual plants to erect herbaceous perennial plants.

Polygonum species are occasionally eaten by humans, and are used as food plants by the larvae of some Lepidoptera species. Most species are considered weeds in Europe and North America.

Many members of the family Polygonaceae that are now placed in separate genera were at one time or other placed in Polygonum, including species of Fagopyrum, Fallopia, Persicaria and Reynoutria.

P. arenastrum or Equal-leaved Knotgrass (By AnRo0002 -Wikipedia Commons)

A prostrate annual herb of open and trampled ground, especially of well-drained soils, on tracks, paths, roadsides and weedy pavements, around ponds and field gateways. Also occasionally on river shingle and sandy shingle at the tops of beaches (Chater, 2010). Leslie (2019) notes that it can survive in mown turf, and also states that it is “not characteristic of arable fields, although occasionally recorded in stubble”

This aggregate includes the native P. aviculare s.s. and P. boreale and the archaeophytes P. arenastrum and P. rurivagum. A fifth species, P. neglectum, may be overlooked in Britain. In some areas, all these taxa are treated as subspecies.

Close-up of P. aviculare or Knotgrass (By Anneli Salo – Wikipedia Commons)

An annual herb of open and disturbed ground, including arable land, gardens, waste places and seashores. It can occur in large quantity, and the species remains a significant agricultural weed.

Wildlife and Other Uses:

Many species of insects feed on knotgrass, including the eponymous Knot Grass moth, Acronicta rumicis, whose larvae are phytophagous on the leaves. The UK’s Database of Insects and their Food Plants lists 113 species which are known to feed on this plant in Britain, of which 10 are beetles, 2 are flies, 8 are Hemiptera (bugs and aphids), and the remaining 93 Lepidoptera (butterflies and moths).

Young leaves and plants can be eaten raw or cooked. Used as a potherb, they are very rich in zinc. Seed can be eaten raw or cooked. Rather small and fiddly to utilize, they can be used in all the ways that buckwheat (Fagopyrum esculentum) is used, either whole or dried and ground into a powder for use in pancakes, biscuits and piñole. The leaves are a tea substitute.

Knotgrass is a safe and effective astringent and diuretic herb that is used mainly in the treatment of complaints such as dysentery and haemorrhoids. It is also taken in the treatment of pulmonary complaints because the silicic acid it contains strengthens connective tissue in the lungs. It was formerly widely used as an astringent both internally and externally in the treatment of wounds, bleeding, piles and diarrhoea. Its diuretic properties make it useful in removing stones. An alcohol-based preparation has been used with success to treat varicose veins of recent origin.

Applied externally, it is an excellent remedy to stay bleeding of the nose and to treat sores. Recent research has shown that the plant is a useful medicine for bacterial dysentery. Of 108 people with this disease, 104 recovered within 5 days when treated internally with a paste of knotweed.

Caution!!

 Although no specific mention has been made for this species, there have been reports that some members of this genus can cause photosensitivity in susceptible people. Many species also contain oxalic acid (the distinctive lemony flavour of sorrel) – whilst not toxic this substance can bind up other minerals making them unavailable to the body and leading to mineral deficiency.

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.

P. cognatum or Indian Knotgrass or Madimak (By Krzysztof Ziarnek, Kenraiz – Wikipedia Commons)

The madimak has larger leaves than most other species of Polygonum. It is one of the widely known traditional edible plants in Turkey particularly Central Anatolia Region. To be able to compensate increasing demand easily and supply the plant to the markets, farmers started cultivating madimak in Central Anatolia.

Bistorta spp.

The Latin name bistorta, from bis (“twice”) + torta (“twisted”), refers to the twisted appearance of the root.

B. officinalis or Common Bistort (By Jerzy Opioła – Wikipedia Commons)

A perennial herb of base-poor soils in damp pastures, hay meadows, riverbanks, roadside verges, in tall-herb communities in river valleys, and on mountain ledges and roadsides. Many colonies originate as garden escapes or throw-outs; for example, Chater (2010) reports the cultivar ‘Superba’ from damp woodland and a roadside verge; conversely, Lockton & Whild (2015) suggest that some churchyard plants in Shropshire may represent the remnants of previously more widespread populations.

Various Uses:

This species is grown as an ornamental garden plant, especially the form ‘Superba’ which has larger, more showy flowers, and has gained the Royal Horticultural Society’s Award of Garden Merit. It is suitable for use as a marginal or in bog gardens.

Bistort has been cultivated as a vegetable, its roots, leaves, and young shoots being steamed or boiled. Many of its occurrences in the wild may be as a garden escape.

In Northern England, the plant was used to make a bitter pudding in Lent from a combination of the leaves, oatmeal, egg, and other herbs. It is the principal ingredient of dock pudding or Easter-Ledge pudding. The roots are also eaten in Russia and northern Asia.

Bistort has been used traditionally for medicinal purposes. The roots are rich in tannic and gallic acids and both these and the leaves have been used to treat wounds

B. amplexicaulis or Red Bistort (By Dinkum – Wikipedia Commons)

A tufted perennial herb, naturalized on roadsides, hedgebanks and waste ground. Plants have rarely been observed to set seed in the wild in Britain and Ireland, and many populations appear to be marginal escapes from gardens, persistent plantings, or to have originated from dumped garden waste.

Numerous cultivars have been developed for garden use, including ‘Firetail’.

B. vivipara or Alpine Bistort in habitat (By Bjoertvedt – Wikipedia Commons)

A short, tufted perennial herb, usually found on base-rich substrates and less frequently in acidic conditions. It grows on wet rocks, consolidated screes, in grassland and in damp flushes in the mountains, and it is often abundant in montane pastures. Reproduction is mostly by bulbils at the base of the inflorescence, frequently carried down to lower levels by streams, but also distributed by wind and by birds such as Ptarmigan Lagopus muta. 

Edible Uses:

The bulbils can be stripped from the lower flower stalks and eaten raw. The young roots are edible raw, while older ones must be cooked. The young leaves can be eaten raw or cooked.

The roots are eaten in Russia, especially by the Samoyed peoples

Bistorta affinis cultivar Donald Lowndes or Himalayan Bistort taken at the Royal Botanical Gardens Edinburgh (Syn. Persicaria, By Jambamkin – Wikipedia Commons)

Bistorta affinis is a creeping, densely tufted, mat-forming perennial, growing to 25 cm (10 in) tall by 60 cm (24 in) broad. The narrow elliptic leaves are white on the underside because of a waxy coating. This plant is not found in the Plant Atlas Online but is found in the Flora of Birmingham and the Black Country as a garden escape.

It is used ornamentally as groundcover. Under the synonym Persicaria affinis the following cultivars have gained the Royal Horticultural Society‘s Award of Garden Merit:

Fallopia spp.

F. baldschuanica or Russian-vine/Mile a minute plant (By AnRo0002 – Wikipedia Commons)

A vigorous, fast-growing, climbing perennial, widely grown in gardens from where its vine-like stems spread out to festoon trees, telegraph poles, walls, scrub, hedges, railways and neglected outbuildings, usually close to human habitations. Also reported from coastal habitats, in particular sand dunes and cliffs.

Fallopia baldschuanica is grown as an ornamental plant for its flower-laced vines. The white flowers are decorative and provide nectar and pollen for the honey bee.  As it is fast-growing, it is used as cover for unsightly fences and other garden structures.

Plant with caution since it’s extremely fast-growing and can end up choking everything in its path!

A climbing or scrambling annual herb, found as a weed of arable land, especially spring-sown crops, as well as gardens, pavements, waste places, refuse tips and on roadsides. 

Reynoutria spp. or Knotweeds

R. japonica or Japanese Knotweed in a Swedish garden (By W.carter – Wikipedia commons),

R. japonica or Japanese Knotweed (neophyte)

A persistent rhizomatous perennial forming dense thickets on waste ground, refuse tips, roadsides, railway banks, along canal, stream and riverbanks, and on sea-loch shores. Spread is rhizomatous, and many populations are established by the unintentional movement of root fragments within topsoil. It is also dispersed in garden waste, and by floodwaters. 

This is a fast-growing and strong clump-forming perennial, with tall, dense annual stems. Stem growth is renewed each year from the stout, deeply-penetrating rhizomes (creeping underground stems).

From RHS Website:

  • The RHS accepted botanical name for Japanese knotweed is Reynoutria japonica 
  • You may also see it referred to by the synonyms Fallopia japonica, Polygonum cuspidatum and Polygonum reynoutria 
  • Japanese knotweed is an invasive non-native plant listed on Schedule 9 of the Wildlife and Countryside Act 1981 
  • Correct identification is key, as there are several plants commonly mistaken for Japanese knotweed! 
  • Mortgage applications and buying and selling properties can be affected by Japanese knotweed  
  • Hiring a company that specialises in invasive weed control is often the best way to deal with Japanese knotweed

It is a very costly affair to have it removed see more here:

The Japanese Knotweed was introduced in the Victorian age as an attractive foliage and flowering, ornamental plant and there is still one, but a much smaller growing variety grown at present for gardens called Fallopia japonica var. compacta:

I do realize the Japanese Knotweed is too greedy and may not give enough back to earn its keep. But what if the soil is infertile or useless for anything better and there are no buildings it can interfere with?

What they have done in an experiment to control Japanese Knotweed in the Netherlands is to let  a rare breed of pigs loose on it which consume the tops as well as dig out and eat the rhizomes! This sort of control makes good sense to me!

Uses:

As a source for honey:

Japanese knotweed flowers are valued by some beekeepers as an important source of nectar for honeybees, at a time of year when little else is flowering. Japanese knotweed yields a monofloral honey, usually called bamboo honey by northeastern U.S. beekeepers, like a mild-flavoured version of buckwheat honey (a related plant also in the Polygonaceae).

The young stems are edible as a spring vegetable, with a flavour similar to rhubarb. In some locations, semi-cultivating Japanese knotweed for food has been used as a means of controlling knotweed populations that invade sensitive wetland areas and drive out the native vegetation. It is eaten in Japan as sansai or wild foraged vegetable.

It is used in traditional Chinese and Japanese medicine to treat various disorders through the actions of resveratrol, although there is no high-quality evidence from clinical research for any medical efficacy.

Ground-feeding songbirds also eat the seeds.

Bee lovers have found another use for Japanese knotweed. The hollow stems are often cut into lengths and bundled for use as native bee habitat. The stem diameters vary just enough to provide suitable housing for a wide range of tunnel-nesting bees, including mason bees and leafcutters.’

A robust rhizomatous perennial herb, reaching a height of up to 5 m and forming extensive thickets, mainly in urban habitats, brownfield sites, waste ground, and roadsides, but also in woodland and on banks adjacent to rivers and on lake and sea-loch shores.

From PFAF:

  • Young shoots in spring can be eaten raw or cooked.
  • They can be added to salads or cooked as an asparagus substitute.
  • They have an acid flavour and we find that they are more like a rhubarb substitute.
  • Older stems and shoot tips are cooked. The stems are best peeled. Tasting like a mild version of rhubarb, they have a superior quality with a hint of lemon in the flavour.
  • Seed is cooked. The seed can be ground into a powder and used as a thickener and flavouring in soups etc, or as an extender in flour. It is rather small and fiddly to utilize.

A rampant, rhizomatous perennial herb, locally forming large stands on roadsides, the banks of canals and railways, streams and riversides, and in the grounds of large estates. These are similar habitats to those of R. japonica, with which it often grows. Male plants of this hybrid show some fertility, and more than one clone is present in some sites.

Specimen of Muehlenbeckia complexa or Wireplant growing in Freiburg Botanical Garden showing its wiry growth (By Daderot – Wikipedia Commons )

Muehlenbeckia complexa or Wireplant

A large, woody, sprawling or weakly climbing deciduous shrub, grown in gardens in mild climates and becoming established on cliffs, rocky slopes and walls, in hedgerows and quarries, and on waste ground. More recently, records from arable and dune habitats have also been made. It also occurs as a relic of cultivation. This species is considered to have negative impacts on native biodiversity in some parts of its non-native range (e.g. in California), and the number of recent records noting well-naturalized, dense stands of this plant suggests that it is starting to become a problem in some parts of Britain and Ireland.

Ornamental Uses and Ecology:

This plant is an interesting garden plant which I first saw in Cornwall. In its native New Zealand it plays a key role sealing human and natural disturbances on the forest edge. It also suppresses the growth of introduced weeds there, such as blackberry, and promotes increased insect diversity.

The best known type of Rhubarb! (By Evan-Amos – Wikipedia Commons)

Rheum spp. or Rhubarbs

Rheum is a genus of about 60 herbaceous perennial plants in the family Polygonaceae. Species are native to eastern Europe, southern and eastern temperate Asia, with a few reaching into northern tropical Asia. Rheum is cultivated in Europe and North America. The genus includes the vegetable rhubarb. 

A large, rhizomatous, perennial herb which is occasionally persistent in rough or marshy grassland, in woodland, on roadside verges, by streams, in ditches, and in waste ground. It also occurs as a relic of cultivation.

Grown as a bold ornamental plant here especially the cultivar ‘Atrosanguineum’.

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.


An insect spray is made from the leaves. This spray is also said to help prevent clubroot of brassicas.

Edible Uses:

According to PFAF: 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.

Rhubarb leaves and shafts (By Dieter Weber photo taken in a private garden in Kiel, Wikipedia Commons)

R.  × ⁠rhabarbarum or Rhubarb (A cultivated hybrid (alien × alien))

A rhizomatous perennial herb usually recorded as single or few but highly persistent clumps by old houses, crofts and farms, in abandoned gardens or allotments, on waste ground, on tracksides and roadsides, field margins, disused railway lines and railway cuttings, river and stream banks and in secondary woodland. Plants are usually outcasts or relics of cultivation; more isolated colonies can originate from rhizome fragments washed down in streams and rivers.

Edible Uses:

Rhubarb is botanically a perennial vegetable, but it’s treated and used culinarily like a fruit, particularly in desserts. 

The precise origin of culinary rhubarb is unknown.

The species Rheum rhabarbarum (syn. R. undulatum) and R. rhaponticum were grown in Europe before the 18th century and used for medicinal purposes. By the early 18th century, these two species and a possible hybrid of unknown origin, R. × hybridum, were grown as vegetable crops in England and Scandinavia. They readily hybridize, and culinary rhubarb was developed by selecting open-pollinated seed, so its precise origin is almost impossible to determine.

In Britain, 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” in Yorkshire between Wakefield, Leeds, and Morley.

Some interesting History of Rhubarb in Europe and the B.I.:

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 explorer 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 1403–1405 to Timur in Samarkand: “The best of all merchandise coming to Samarkand was from China: especially silks, satins, musk, rubies, diamonds, pearls, and rhubarb….”

The high price, as well as the increasing demand from apothecaries, stimulated efforts to cultivate the different species of rhubarb on European soil.

R. rhaponticum × R. officinale came to be grown in England to produce the roots.  R. alpinus was also allowed to grow wild. The local availability of the plants grown for medicinal purposes, together with the increasing abundance and decreasing price of sugar in the 18th century, galvanised its culinary adoption. Grieve claims a date of 1820 in England. Rhubarb was harvested in Scotland from at least 1786, having been introduced to the Botanical Garden in Edinburgh by the traveller Bruce of Kinnaird in 1774. He brought the seeds from Abyssinia and they produced 3,000 plants.

Finally find here some tips on how to grow rhubarb.

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