Rhubarb

Article By:

Carew, H. John Michigan State University, East Lansing, Michigan.

Last reviewed:August 2020

DOI:https://doi.org/10.1036/1097-8542.588000

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• Rhubarb, published June 2014:Download PDF Get Adobe Acrobat Reader

An herbaceous perennial, Rheum rhabarbarum or Rheum rhaponticum, of Mediterranean origin, belonging to the plant order Polygonales in older botanical classifications or Caryophyllales in newer classifications. Rhubarb (Rheum rhabarbarum or Rheum rhaponticum; see illustration) was assigned to the plant order Polygonales in older botanical classifications, but has been reassigned to the order Caryophyllales in newer classifications. It is grown for its thick petioles (stalks or stems that support the leaf blades), which are used mainly as a cooked dessert; frequently, it is called the pie plant. The leaves, which are high in oxalic acid content, are not commonly considered edible. Propagation is by division of root crowns. Victoria, Macdonald, and Valentine are popular varieties (cultivars). Commercial production is limited generally to areas where crowns may become dormant for 2–3 months each year. Outdoor rhubarb is a common garden vegetable in most areas of the United States, except the South. Harvesting begins in the spring and continues for 6–10 weeks. Commercial plantings are renewed every 4–8 years. In the United States, Washington, Oregon, and Michigan are important centers for rhubarb production. Rhubard can be grown in the field or in greenhouses. When grown in greenhouses, it is called forced or hothouse rhubard. In this type of cultivation, two- or three-year-old field-grown crowns are moved into darkened forcing structures in late winter and forced at 55–60°F (12.8–15.6°C) to obtain petioles of a bright-red color. See also: Caryophyllales; Horticultural crops; Plant propagation; Polygonales

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