Definition of saviour's flannel in English:

saviour's flannel

(US savior's flannel)

noun

rare
  • (Also more fully "our saviour's flannel") any of several plants which have hairy or downy leaves; especially viper's bugloss (Echium vulgare), great mullein (Verbascum thapsus), and lamb's ears (Stachys byzantina).

Origin

Late 19th century; earliest use found in James Britten (1846–1924), botanist and Roman Catholic propagandist.