Rhubarb is now grown all over the world wherever the climate is suitable for its growth. The precise origin of the culinary rhubarb we know today is unknown because the plant hybridizes readily, and culinary rhubarb was developed by selecting open-pollinated seed, so its precise origin is almost impossible to determine.
Rhubarb is a very cold hardy perennial that generally goes dormant through winter with the tops dying back in autumn, and the roots can withstand freezing temperatures extremely well. In very early spring fresh new leaves appear and the plant quickly produces large clumps of enormous dark green leaves, up to 60cm across, borne on proportionately large stems, which are 2.5cm or more in diameter and 60 to 90cm in length. Later in the season a large central flower stalk may appear bearing numerous small greenish white flowers, the flowers are followed by angular winged fruits, each containing a single seed.
Rhubarb stalks are poetically described as "crimson stalks", but the colour can vary from the commonly associated crimson-red, through speckled light pink, to simply light green. The colour results from the presence of anthocyanins, and varies according to variety and production techniques. It does not matter which colour stems you have, as the colour is not related to their suitability for cooking.
Wild rhubarb is indigenous to Asia where it thrives in the cold climates of Mongolia, the Himalayas' and Siberia by going dormant in winter, and the dormant roots are able to survive the frozen soil. Throughout these regions at this time, the use of rhubarb was solely medicinal rather than culinary.
The Chinese call rhubarb "the great yellow" (dà huáng), and it appears in The Divine Farmer's Herb-Root Classic, a book on agriculture and medicinal plants, traditionally attributed to Shennong, a mythological Chinese ruler known as the first Yan Emperor, first of the legendary Flame Emperors, and the creator of agriculture in China. Shennong is translated as "Divine Farmer" or "Divine Husbandman" and researchers believe the text is a compilation of even older oral traditions that were written down at this time. Sadly the original text no longer exists, but it is thought to have been compiled between about 206 BC and 220 AD. Shennong became a deity in Chinese and Vietnamese folk religion, and is still venerated in China, as well as in Vietnam where he is referred to as Thần Nông.
The first documented uses in western civilization are 2,100 years ago when rhubarb roots were an ingredient in numerous Greek and Roman medicines. Pedanius Dioscorides (40–90 AD) a Greek physician employed in the Roman army; and also a botanist and author of De materia medica, a 5-volume Greek Encyclopaedia about herbal medicine and related medicinal substances, referred to rhubarb as “Rheubarbarum”, noting that it grew beyond the Bosphorus River in Turkey, and had good medicinal properties.
Most experts conclude that the name rhubarb comes from a French word "rubarbe" that came from the Medieval Latin word "Rheubarbarum", or from the Greek, "Rha barbaron". Rha was a name given to the place where rhubarb grew wild on the banks of the Volga River, and Barbarum is a term for ‘foreign’, because to the Greeks and Romans it was the foreign people who lived around this river that grew this fascinating plant. So when you put the two words together you get a word that sounds something like rhubarb. Even the Afrikaans name for rhubarb is “rabarber”, and now you know why?
The rhubarb plant has grown wild for centuries along the banks of the Volga River which flows through Central Russia to Southern Russia and into the Caspian Sea, and it was most likely brought there by Eurasian tribes, such as the Scythians, Huns, Magyars, or Mongols, and by the 16th century rhubarb was grown extensively in Russia. It started arriving in Europe via the new maritime routes, or overland through Russia, and the so called "Russian Rhubarb" was highly valued.
The cost of transportation across Asia made rhubarb expensive in medieval Europe, and it was several times the price of other valuable herbs and spices such as cinnamon, opium, and saffron. The high price, together with the increasing demand from apothecaries, stimulated efforts to cultivate different species of rhubarb on European soil. However, rhubarb was not grown commercially in Europe until it became more freely available via The Silk Road, reaching Europe through the ports of Aleppo and Smyrna, where it became known as "Turkish Rhubarb".
The Venetian writer, explorer and merchant, Marco Polo, travelled through Asia along The Silk Road searching for the place where the plant was grown and harvested. He finally found it in cultivation in the mountains of Tangut province, which is now the north-western Chinese provinces of Gansu and Shaanxi, and the southwestern portion of the Inner Mongolia Autonomous Region of China.
By 1753 rhubarb was widely cultivated in France and the Netherlands, and arrived in England around the same time, via these two countries. Rhubarb was harvested in Scotland from at least 1786, having been introduced to the Botanical Garden in Edinburgh in 1774, by the traveller, Bruce of Kinnaird, who brought rhubarb seeds from Abyssinia home with him. The seeds germinated well, producing 3,000 plants.
Because medicine made from the roots of the rhubarb plant was widely used with no bad side effects, early in the 17th century the English were the first nation brave enough to experiment and eat other parts of the plant. Probably because they look like chard, they sadly decided to start with the leaves, not knowing that they contain a toxic amount of oxalic acid and are poisonous. The ensuing cramps and nausea that followed, plus a couple of deaths, dissuaded everyone from eating rhubarb - for about two hundred years!
Despite rhubarbs bad reputation as an edible, it continued to be cultivated for its medicinal uses, and amazingly, the English and the Europeans eventually discovered that the stalks were edible! This, coupled with an abundance of sugar at very low prices in the 18th century, galvanised rhubarb as a culinary delight for the common people, and its popularity reached a peak between the two world wars.
Many historians say that rhubarb first came to America in the 1820’s, entering the country in Maine and Massachusetts and moving west with the settlers, while others say it was brought in before the 1800’s, as John Bartram from Philadelphia was growing medicinal and culinary rhubarb seeds sent to him by Peter Collinson as early as the 1730’s.
Today The Royal Horticultural Society has the United Kingdom’s national collection of rhubarb and The Walled Kitchen Garden at Clumber Park is home to over 130 varieties, making it the second largest collection in the world. The collection is proudly tended to by specialist gardeners, helping the Society to conserve some of the UK's most endangered rhubarb varieties. Click here to visit the website.
Health Benefits:
Rhubarb’s medicinal uses began at least 5,000 years ago in ancient China and Tibet, where the roots of two species known as “Chinese Rhubarb” (Rheum officinale and Rheum palmatum) were used primarily as a cathartic, or purgative. Dried rhubarb root is still used today to keep the body cleansed, and to treat chronic constipation, haemorrhoids, menstrual problems, liver ailments and gall bladder pains.
It is noteworthy to mention here that the medical efficacy of rhubarb roots varies significantly by variety, and the original Chinese varieties, remain the most efficacious, while some varieties have no laxative value whatsoever. Unfortunately, rhubarb hybridizes easily and there are no standards in place for the names of varieties or cultivars. Therefore it is very difficult to know the pedigree of any particular plant. Just calling it “Chinese” does not mean it is the exactly the same as the early strains.
The stems of rhubarb are classified as a superfood for their ratio of health benefits to calories and slimmer’s love rhubarb because it only has 7 calories per 100 grams. It’s contains negligible fat and is low in sodium, while offering a good source of dietary fibre. Raw rhubarb is 94% water, 5% carbohydrates, and 1% protein. It supplies 88 kilojoules (21 kilocalories) of food energy, and is a rich source of vitamin K (28% of the Daily Value, RDV), and a moderate source of vitamin C (10% RDV).
Rhubarb Pie Image by Patricia York from PixabayIn the Kitchen:
According to Alan Davidson (Oxford Companion to Food,) the first recorded rhubarb recipe found in the West appears in a cookbook by Maria Eliza Rundell, published around 1806. And surprise, surprise, it was for rhubarb tart! For many of us, the rest is just history, and any mention of rhubarb conjures up only one thing - hot rhubarb pie and cream. It’s no wonder that rhubarb is fondly given the nickname “pieplant” in the United States.
However, rhubarb goes beautifully in savoury dishes, and there is a world of mouth-watering rhubarb recipes online, so perhaps it’s time to think outside the pie and expand your horizons when it comes to cooking with rhubarb. Here are some ideas I found online just to get your juices going.
Sweet and sour is a classic pairing, and the addition of rhubarb to this “Rhubarb and Okra Sweet and Sour Soup” may be a surprising addition, but the results are beautiful.
“Chinese Pork Ribs with Spicy Rhubarb Sauce” sounds amazing, perhaps finished off with Chinese “Rhubarb & Custard Tart”
“Persian Lamb and Rhubarb Stew” (Khoresht Rivas) is a traditional Middle Eastern dish that uses rhubarb as a vegetable in a one-of-a-kind stew that is full of fresh herbs, and the rhubarb chunks add a bight tartness to this meaty dish.
“Rhubarb Chutney with Strawberries and Ginger” is a tangy and sweet Indian rhubarb chutney that, while being vegan, vegetarian, low carb, paleo, and gluten-free, is incredibly delicious, and the perfect condiment for a spring and summer braai.
And, if you fancy a drink, this sharp and refreshing “Rhubarb and Ginger Sour” really hits the spot, combining rhubarb and ginger liqueur with lime juice and green tea syrup.
No matter what your taste preferences are, just celebrate rhubarb season in the best way possible, and try something new.
In the Garden:
Be adventurous when planting rhubarb in the garden and try planting it in a perennial or mixed shrub border. It makes a gorgeous, tropical-looking filler plant, and because it will grow in sun or semi-shade, it will happily grow between other plants. Take care not to disturb the root system of your rhubarb plants when inter-planting, and remember that it can live for a very long time without being disturbed, so site it where it can be left alone to do its thing. It can also be grown in a large pot.
Strawberry Plants Image by Fruchthandel Magazin from PixabayCompanion planting:
Companion planting is a time-tested gardening method that has been passed down for generations, and it has never been more relevant than right now, as it helps to deter pests, thus reducing the need to spray, resulting in healthier and more productive crops. To achieve this, farmers and gardeners plant specific crops that enjoy one another’s company in close proximity to each other. On the other hand, organic gardeners also know that certain plants really don’t get along very well together, and are bad companion plants, like rhubarb and sunflowers – they just don’t gel!
As a general guardian, rhubarb is a great companion plant for just about everything in a vegetable garden. Here are just a few examples of good companion plants for rhubarb:
Strawberries and rhubarb are just as good together in the garden as they are in the kitchen, and they are both harvested at the same time. They don’t compete with each other for nutrients or space, and the strawberries act as a ground cover for rhubarb, forming living mulch for the soil.
Rhubarb’s ability to deter whiteflies with its scent makes it great to plant with all members of the Brassica family, like broccoli, cabbage, kale, kohlrabi, and cauliflower.
Likewise, rhubarb protects beans by repelling black fly aphids, and in turn the rhubarb benefits from the extra nitrogen beans put back into the soil.
Alliums like garlic and onions help to deter leaf beetles and weevils from destroying the leaves and stalks of young rhubarb.
How to make an insecticide with rhubarb leaves:
Companion planting does not mean that you will never have pests and diseases in the garden, you will, but with this method of gardening, if necessary, homemade or commercial organic sprays are used. Rhubarb is a great example of this, as the poisonous leaves, which contain oxalic acid, are used as an effective insecticide spray against caterpillars, aphids, whitefly and many other plant eating insects.
You may be wondering if you can use poisonous rhubarb leaf spray on your vegetables, and the answer is yes, as long as you are not currently harvesting and eating them. It can even be used close to harvesting time as long as you wait a day or two before harvesting, and you wash the veggies well, as you would do after using any other pesticide.
Rhubarb spray can be used on most shrubs, trees, fruits etc., but if you have something very exotic and are concerned, spray a small branch of the plant and wait 24 hours to see if any damage occurs, before spraying the entire plant.
This spray is easy to make, and the measurements don’t have to be perfect, but try to keep a ratio of 1:5 ratio, for example, if you’ve got one cup of chopped rhubarb leaves, use five cups of water. Another way to judge ratios is to pour in just enough water to cover the leaves in the pot. Simmer the leaves gently with the lid on, for about half an hour, then allow to the solution cool down.
Next, using a strainer, remove all the leaves from the pot, squeezing all the liquid out of the leaves. Add a little liquid dish detergent, and using a finer sieve pour the solution into a spray bottle. That’s all there is to it! Try to spray during the cooler times of the day so the solution does not evaporate too quickly.
Rhubarb Plant Image by Di Reynolds from Pixabay
Cultivation:
Rhubarb is an adaptable plant that will grow in many of South Africa’s growing regions, but does best in temperate to cold districts that have a mild summer with good rainfall. The plant will struggle in very hot and humid climates because rhubarb requires an annual cold period of 7 to 9 weeks at 3°C, known as ‘cold units’, to grow optimally. In the winter rainfall regions, or drier inland regions, it will require regular watering during dry spells.
Green rhubarb usually becomes dormant in winter, while the red varieties can produce all year round in warmer climates. In very cold regions most varieties will go dormant in winter. The main thing to bear in mind when growing rhubarb is it requires a place where it can grow un-disturbed for several years. It can also be grown in containers, but it does have a large root system, so pots or planter boxes have to be deep and wide.
In milder summer regions rhubarb thrives in full sun, but in the hotter parts of the country, some shade, especially at midday, would be beneficial for the plants, together with plenty of water.
Rhubarb will grow in most fertile garden soils, even clay, as long as the soil drains very well, but because it is long-lived and has a voracious appetite, it is essential to prepare the planting beds well, adding lots of organic matter like compost and mature kraal manure. At planting time you can add a small handful of bone meal or blood and bone, worm castings, or even just some organic 2:3:2 to the planting hole. Be careful not to damage or disturb rhubarb roots when cultivating round the plant.
Although rhubarb loves regular watering, it hates being waterlogged, and this can cause crown rot. Water young plants, and those growing in pots regularly, and established plants growing in garden beds will need to be watered deeply at least once a week during dry weather, preferably in the cooler late afternoon temperatures.
If your stems are flopping over, or there are flowering stems, the plant is suffering from heat stress, so ensure that the plants are watered regularly, and mulch well to keep the roots cool and moist. Flowering spikes may also suggest that the crowns need to be divided.
The best way to plant rhubarb is to plant crowns, which are offsets cut from divisions of vigorous parent plants, and usually there will be a piece of root with at least one dormant bud visible. Plant them in spring or late autumn, while they are dormant or at least growing slowly. When you plant the crowns, leave the ‘eye’ (where the leaves emerge) at ground level and press the soil down around the roots firmly. Small potted plants are available from garden centres, and this may be the best option if you want a quicker rhubarb harvest.
However, if you like the challenge of growing from seed, rhubarb can be started from seed quite easily, but the plants take up to 3 years to become established and reach a size that you can harvest from, so in a normal sized garden it’s more common for rhubarb to be planted from crowns. However, if you want to plant a large patch, seeds are definitely a cheaper way to go.
Sow rhubarb seed into trays or directly into well-prepared beds in spring, but in warm regions it is best to sow in late summer or autumn. Soak the seeds in warm water for a few hours before planting, and for direct sowing, plant a couple of seeds together in clumps spaced about 90cm apart, with a distance of 90cm between the rows.
The seed should take 2 to 3 weeks to sprout and the soil needs to be kept moist throughout this time. Once the seeds growing in trays have germinated and are fairly well developed they can be planted into garden beds at the correct spacing for your variety. Those sown directly in clumps will need thinning, and because the quality of seed-grown rhubarb can vary, you must be ruthless in selecting only the strongest and most vigorous plant in each clump to grow on, by tugging the less desirable ones out gently by hand.
Maintaining soil fertility is the secret to keeping rhubarb plants healthy, so maintaining a thick layer of mulch around the base of the plants is essential, using straw, or any available organic matter like leaf mould and grass clipping, combined with compost or well-rotted manure. Spread this around the plants, and then soak the mulch and roots with a liquid manure or fish emulsion. This will provide lots of nitrogen to feed the stems and suppress flower production. In summer, mulch also helps to keep the weeds down, retains moisture, and goes a long way in preventing heat stress by keeping the roots cool. And, in winter, mulch keeps the roots warm and snug.
Rhubarb is quite a hungry plant and to encourage more stems and leaves, feed at least once a month throughout the growing season with a liquid fertiliser for leafy plants, or any balanced organic fertiliser that is high in nitrogen. Potted specimens will need feeding more frequently.
Harvesting:
In the first year of growth it is best not to harvest too much, or not at all, as the plant will take at least one season to establish. Once established, you can harvest every 3 or 4 weeks during summer, by tugging the stems downwards and outwards in a gentle motion. Cutting the stalks with a knife will leave a stub which can attract fungus and pests. Remember to always remove the leaves before you use your harvest. Any flowering stalks should be cut out immediately as the plant will stop producing leaf stalks when in bloom.
Rhubarb Forcer Pot. Image by Alyx H from PixabayForcing Rhubarb:
In late winter rhubarb can be 'forced' for an early spring crop, by watering lightly and then covering the dormant crowns to stop light from reaching the emerging rhubarb stems. You can use a bin or bucket, or a traditional terracotta rhubarb forcer, in fact any cover that blocks out the light and is at least 45cm high is fine. Simply place this over the dormant crowns, and in very cold regions, to speed up forcing even more, insulate the outside of the pot with a thick layer of straw or bubble wrap.
Check on your plants every week or so, as your rhubarb plants will have developed tender stems after about five to eight weeks. This early growth will be pale, but can be harvested for use in cooking when the stems are only about 20 to 30cm long. Forcing rhubarb in this way provides a useful crop at a time when there is little else in store from the garden.
Only well-established rhubarb plants should be forced, and then only every alternate season, as forcing takes a lot of energy, even from established plants. Mulching, feeding and regular watering after forcing will enable the plants to flourish through the rest of the season.
Moving, Splitting & Dividing Rhubarb:
Healthy rhubarb clumps don’t have to be divided, and can be left undisturbed for up to 5 years or more. However, if after several years you wish to split and divide the crowns to increase your stock, or just to give the plant renewed vigour, dividing rhubarb is easy, and can be done at any time, although the best time is when the plant is completely dormant in winter, or in late autumn or early spring when growth is slow.
Simply dig the existing crown up, then using a spade, garden fork or even old kitchen knife, split the crown into sections, with each section containing 1 to 3 buds. Also ensure that each section has a good set of roots attached. Discard any tough, woody material from the centre of the crown. Replant the smaller crowns in moist, fertile soil and water well. Some of the root structure will be damaged when lifting it, so stalk production will not be so good for a few months and its best not to harvest in the first year.
If you have too many rhubarb divisions to replant, wrap them up in moist paper towels and give them to family and friends, who wouldn’t love to receive a gift of rhubarb!
Problems, Pests & Diseases:
Although rhubarb suffers from no serious insect problems, watch out for whiteflies, caterpillars, snails and slugs.
Fungal diseases are more prevalent in humid regions and grey mould can become a problem if not treated.
Although rhubarb loves regular watering, it hates being waterlogged, and this can cause crown rot, the most common fungal infection of rhubarb. It starts at the base of the stalks, and causes the crowns to turn brown and soft. Unfortunately there’s no remedy. The plant can also be prone to honey fungus, and viruses. Any of these diseases will weaken the plant, and its best to discard the affected plants, and start again on a new site.
If your stems are flopping over, or there are flowering stems, the plant is suffering from heat stress so ensure that the plants are watered regularly, and mulched to keep the roots cool and moist. Flowering spikes may also suggest that the crowns need to be divided.
Warning:
The leaves of rhubarb are toxic to cats, dogs, horses and people.
They contain poisonous substances, including oxalic acid, and the long term consumption of oxalic acid leads to kidney stone formation in humans. For this reason, rhubarb stems damaged by severe cold should not be eaten, as they may be high in this acid, which migrates from the leaves and can cause illness.
Although rhubarb root is used medicinally, never start a home treatment before consulting with a health professional first.