Zone 6 Salvias are generally hardy to -10 degrees F. They are mainly herbaceous perennials with soft foliage that dies back to the ground for winter. Others are subshrubs -- semi-woody perennials.
(Shell Dancer Sage) So many sages combine resilience and loveliness. This includes Salvia 'Shell Dancer', which withstands heat and drought yet has delicate looking blossoms and lush green foliage.
(Yunnan Sage or yun nan shu wei cao) Yunnan Sage's tall spikes of violet-to-purple flowers bloom from summer into fall. Native to Southwestern China's provinces of Yunnan, Guizhou and Sichuan, it grows on shady, grassy hillsides and along forest margins at elevations up to 9,500 feet.