Rhubarb is a unique, tart perennial plant that signals the arrival of spring, commonly featured in pies, crumbles, and jams. Its vibrant red or green stalks often lead people to mistakenly classify it as a fruit due to its culinary use in sweet dishes. The plant possesses a complex history spanning continents and thousands of years, a past that was initially far more medicinal than culinary. The story involves ancient trade routes, staggering costs, and a fundamental shift in how people learned to use it.
The True Geographic Origin and Ancient Use
The original homeland of the rhubarb plant lies deep within the frigid environments of Central Asia, specifically Siberia, Mongolia, and parts of China. Belonging to the genus Rheum, the plant evolved to thrive in cold climates, developing thick, fleshy roots that were initially its most valuable part.
Historical records from China document the use of rhubarb dating back over 5,000 years, or at least to 2,700 BCE. The plant was cultivated strictly for its dried root (rhizome), not its stalks. The dried root was prized as a potent medicine for its laxative and purgative properties.
These effects were caused by natural compounds in the root, such as anthraquinone glycosides like emodin and rhein. Because of its reliable medicinal qualities, the dried rhubarb root became a highly sought-after commodity in ancient trade.
How Rhubarb Migrated West and Became a Food Source
The movement of rhubarb from Asia to Europe was a slow, expensive process tied to ancient commerce. The dried medicinal root was imported along the Silk Road, with documented trade occurring as early as the 7th or 8th century. Due to the extreme distances, the root was incredibly costly when it reached Western apothecaries.
For centuries throughout the Middle Ages, the price of dried rhubarb root was exorbitant, often exceeding the cost of exotic spices like cinnamon, saffron, and opium. This high value cemented its status as a medicinal luxury item. Roots coming via Russia were particularly prized, sometimes called “Siberian rhubarb.”
The plant’s transition from a medicinal root to a culinary stalk began much later, around the 17th and 18th centuries, first in Britain. This shift was directly linked to the increased availability and affordability of sugar, which was necessary to counter the plant’s intense tartness.
Europeans began cultivating the plant closer to home. They focused on the stalks of varieties like Rheum rhaponticum and Rheum rhabarbarum. This allowed the tart petioles to be used in desserts, earning rhubarb the nickname “pieplant” and cementing its modern role as a food source.
Clarifying Rhubarb’s Botanical Identity and Edible Parts
Despite its common use in sweet dishes, rhubarb is botanically classified as a vegetable. It is an herbaceous perennial in the Polygonaceae family, which also includes buckwheat. The plant cultivated for consumption today is generally a hybrid known as Rheum × hybridum, though it is often still referred to as Rheum rhabarbarum.
The only safe and edible part of the plant is the stalk, or petiole, which contains malic acid, giving it its signature tart flavor. The large, triangular leaves, however, are highly toxic and must never be consumed.
This danger is due to a high concentration of oxalic acid, a nephrotoxin that can cause severe illness, kidney damage, and even death if ingested. Oxalic acid is present in all parts of the plant, but its concentration is significantly higher in the leaves than in the edible stalks. When preparing rhubarb, the entire leafy blade must be completely trimmed away to prevent accidental poisoning.