Mentha × gracilis 'Variegata', described more than 200 years ago, is still being used as an ornamental. The bright vein-banding symptoms that confer the ornamental value to 'Variegata' clones are graft transmissible and can be eliminated after heat therapy and apical meristem culture. This observation led us to investigate the possibility that symptoms are virus-induced. Double-stranded RNA extracted from a 'Variegata' clone was cloned. One of the viruses identified was a member of the Closteroviridae family. This virus, designated Mint vein-banding associated virus, shares sequence similarities with all three genera of the family, making it an important link among the genera of the Closteroviridae. A detection protocol has been developed that readily detects the virus in other mint clones that exhibit vein-banding symptoms.