We don't have synonyms for vervaine yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are vervain, vervine and verlaine.
(n) :
Obsolete spelling of vervain. [Any herbaceous plant in the genus Verbena especially if used for medicinal purposes, primarily Verbena officinalis, common in Europe and formerly held to have medicinal properties.]
(n) :
Obsolete spelling of vervain. [Any herbaceous plant in the genus Verbena especially if used for medicinal purposes, primarily Verbena officinalis, common in Europe and formerly held to have medicinal properties.]