Named for Carl Peter (Pehr or Per) Thunberg (1743-1828), doctor, botanist, student of Linnaeus who collected plants in Japan, Sri Lanka and South Africa. He published Flora Japonica (1784); Prodomus plantarum capensis (2 vols., 1794, 1800); Icones plantarum japonicarum (1805); Flora capensis (1807-1823) on the South African collections, and Voyages de C.P. Thunberg au Japon par le Cap de Bonne-Espérance, les Isles de la Sonde (1796) about his travels. He was elected a Fellow of the Royal Society in April 1788.

Syn of Berberis thunbergii f. atropurpurea 'Helmond Pillar'.