Rabarbaro: Rheum rhabarbarum, Rheum officinale

Rhubarb is a fascinating plant, a giant herb with a millennia-old history that has seen it transform from a precious oriental medicine to a mainstay of Western confectionery. Origin: The entire Rheum genus is native to Central and Eastern Asia (particularly the mountainous regions of China, Tibet, Mongolia, and Siberia). In Europe and America, the most widespread and cultivated species fall into two main categories: Medicinal species: Rheum officinale and Rheum palmatum, historically imported for the medicinal properties of their roots. Food species: Almost exclusively Rheum rhabarbarum, selected over time for its less bitter, more tender, and juicier stems. Botanical Characteristics: A robust perennial herb belonging to the Polygonaceae family, it is related to and similar to some local wild herbs such as sorrel (Rumex acetosa), Rumex scutatus, and Alpine rhubarb (Rumex alpinus). Roots and Rhizome: It has a large, fleshy rhizome and deep roots. This is where the medicinal active ingredients are concentrated. Leaves: They are monumental, palmate or cordate, and can reach considerable size. Caution: The leaf blades are toxic to humans due to the very high concentration of oxalic acid. Petioles (or stems): These are the only edible part of the plant. They are long, fleshy, and their color varies from bright green to pink to deep red. Flowers: In late spring, the plant produces large panicle inflorescences with small white or greenish flowers that rise above the leaves. Fruits: samaras or nuts with a single, perfectly fertile seed, suitable for propagating the plant. History of Use: From Medicine to Dessert Medicinal Use: For millennia, the samara was exclusively a medicinal plant. Already mentioned in the oldest Chinese herbal (the Shennong Ben Cao Jing) in 1700 BC, it was revered for its laxative, purgative, and digestive properties (due to anthracite derivatives). The dried root reached Europe via the Silk Road, becoming a highly prized luxury item, especially in the Middle Ages, often more expensive than saffron or opium. The Food Revolution The transition to the table came late, between the late 1700s and early 1800s in Great Britain. With the availability of cheap sugar, the English discovered that the stalks (until then discarded) lost their strong acidity when cooked with sugar. Today, rhubarb is a key ingredient in Northern European, North American, and Alpine pastry making, prized for its tart, bitter, and sweet contrast in: Jams and compotes (often paired with strawberries to balance their acidity). Baked goods: Tarts, soft cakes, and the celebrated British Apple and Rhubarb Crumble. Syrups, liqueurs, and candied fruit: Used both in cocktail making and as garnishes. Cultivation and ideal climate: It is an extremely hardy plant but has very specific climatic requirements. Climate: It loves the cold and resists winter frosts. It requires harsh winters to enter a complete dormant phase. It tolerates scorching summer heat and dry summers; it thrives best in Northern Europe, North America, and, in Italy, predominantly in cooler hilly or mountainous areas.