saviour's flannel
(US savior's flannel) now rare
noun
(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.