[Wikipedia] China & Japan native: Buddleja davidii (spelling variant Buddleia davidii), also called summer lilac, butterfly-bush, or orange eye, is a species of flowering plant in the family Scrophulariaceae, native to Sichuan and Hubei provinces in central China, and also Japan. (link added by Mary Ann Machi)

[Cal-IPC] Invasiveness: Buddleja davidii (butterfly bush) is a shrub (family Buddlejaceae) with a cluster of pink to purple flowers and narrow leaves found in the San Francisco Bay area and coastal ranges of California, and is invasive in the Pacific Northwest. It is native to China. It favors riparian and bottomland habitat. It is highly regenerative and can spread via dumped garden waste. Seeds are retained on the plant over the winter and they are released in early spring or summer. Seed dispersal can start in late autumn or early winter. (link added by Mary Ann Machi)