Buddleja davidii (spelling variant Buddleia davidii), also called butterfly-bush, orange eye, or summer lilac, is a species of flowering plant in the family Scrophulariaceae, native to most of China except for the far northeast. It is widely used as an ornamental plant, and many named cultivars are in cultivation. The genus was named Buddleja after the English botanist, Reverend Adam Buddle. The species name, davidii, is after the French missionary and explorer in China, Father Armand David, who was the first European to report the shrub. It was found near Yichang by Dr Augustine Henry about 1887 and sent to St Petersburg. Another botanist-missionary in China, Jean-André Soulié, sent seed to the French nursery Vilmorin, and B. davidii entered commerce in the 1890s.
B. davidii was accorded the RHS Award of Merit (AM) in 1898, and the Award of Garden Merit (AGM) in 1941.