Rheum rhabarbarum is a species of flowering plant in the family Polygonaceae, native to a region stretching from southern Siberia to north and central China.

[6] It is native to an area of southeastern Siberia in the Daurian region around and stretching east from Lake Baikal in Russia, and in northern Mongolia.

[7][8] In China, it occurs in the northern provinces of Hebei,[2][9] Heilongjiang,[2][9] Henan,[9] Hubei,[2][9] Jilin,[2][9] Inner Mongolia,[2][9] Shanxi[2][9] and Shaanxi.

exigua is roughly native to some of the same areas, and its European variety has been found to have eaten rhubarb in Finland (it usually feeds on various tree species).

Other species found to eat (garden) rhubarb which occur in the native range of this plant are Arctia caja, Hydraecia micacea, Spilarctia luteum and Xestia baja.

They readily hybridize, and culinary rhubarb was developed by selecting open-pollinated seed, so that its precise origin is almost impossible to determine.