Scopolia carniolica is a perennial herb that favours full shade and reaches about 0.6 m in height. It flowers in the UK from June to August. Native to the Caucasus, it is fully hardy in Britain (H7). All parts are toxic if eaten, so wear gloves and other protective equipment when handling and keep away from pets.

Henbane bell (Scopolia carniolica) is a shade-loving perennial from the Caucasus that flowers June to August and is toxic if eaten.

https://en.wikipedia.org/wiki/Scopolia_carniolica

Scopolia is a genus of four species of flowering plants in the family Solanaceae, native to Europe and Asia. The genus is named after Giovanni Scopoli (1723–88), a Tyrolean naturalist.

Scopolia carniolica

Henbane bell, European scopolia | Scopolia carniolica

A perennial herb in the nightshade family that bears greenish-yellow, nodding bell flowers, Scopolia carniolica var. hladnikiana reaches about 0.6 m. It is native to Slovenia and is poisonous, so avoid ingestion and wear gloves when handling. Flowering in the UK runs from June to August, offering late-spring to midsummer colour in deep shade.

Scopolia carniolica var. hladnikiana is a fully hardy Slovenian perennial with greenish-yellow nodding flowers for deep shade, flowering June to August.