pronounced: REE-um ruh-BAR-buh-rum
Rheum is from the Greek 'ρευμα (rheuma), a stream, flow; rhabarbarum is also Greek, 'Ρα (Rha), the Volga, on whose banks rhubarb grows, and βαρβαρος (barbaros), foreign, outlandish.
The Chinese have used rhubarb medically, especially its roots as a strong laxative, for thousands of years; it is mentioned in The Divine Farmer’s Herb-Root Classic, first complied around 200 BC, possibly by Shennong, a legendary ruler who is believed to have taught the ancient Chinese how to farm. The book includes 365 medicines.
European supplies of rhubarb came from the banks of the River Volga, and it was very expensive, due to the high cost of transportation across Europe – it was several times the cost of other herbs such as cinnamon and saffron, and even of opium. After Marco Polo (1254-1324) found it grown commercially in the mountains of Tangut province, ‘Chinese Rhubarb’ joined ‘Russian Rhubarb’ on the European market.
Rhubarb, of which there are many cultivars and hybrids, is a perennial plant that forms large fleshy rhizomes and has large more-or-less triangular-shaped leaves that grow on long, thick petioles. If the plants are allowed to flower, the tiny flowers are grouped in large compound inflorescences that are greenish white to rose-red in colour. The petioles are the rhubarb stalks that are eaten. They are rich in Vitamin C and in dietary fibre. Their use as a food is comparatively recent, first recorded in 17th century England, after affordable sugar became available. Rhubarb is normally stewed with sugar and used in pies and desserts. It is often cooked with apples or strawberries as sweeteners.
In earlier days, a common sweet for children in parts of the UK, and also in Sweden, was a tender young stick of rhubarb coated in sugar. It is still eaten in this way in parts of northern Europe.
In the UK, the first rhubarb of the year is produced in forcing sheds where as much light as possible is excluded, to produce a sweeter, more tender stalk. It is harvested by candlelight. There is a ‘rhubarb triangle' for such production, around Leeds, Wakefield and Morley in northern England.
The colour of rhubarb stalks is not always the red we normally see: it can be anything from light green through speckled light pink to deep crimson. The green-stalked types are more robust with a higher yield, but the red stalks are more popular with consumers.
Rhubarb leaves contain poisonous substances, including oxalic acid, although one would have to eat quite a lot of the leaves to be poisoned. In the petioles, the concentration of oxalic acid is much lower, only about 2% of the total acidity, which is dominated by malic acid.