The common name of the flowering herb Hypericum perforatum, widely known as St. John’s Wort, reflects centuries of European history, religious tradition, and linguistic evolution. The name connects the plant to a specific moment in the calendar and to ancient ideas about its properties. The designation is divided into two distinct parts, “St. John’s” and “wort,” each possessing a separate and significant origin story that explains how this recognized plant received its name.
The St. John Connection
The first part of the common name is a direct reference to St. John the Baptist, whose traditional feast day is celebrated on June 24th. This date, known as Midsummer, is the pivot point for the plant’s designation. Hypericum perforatum typically reaches its peak bloom around this time in the Northern Hemisphere, displaying bright, star-shaped yellow flowers precisely when the Christian calendar honors the saint’s nativity.
Historically, Midsummer’s Eve and St. John’s Day were important times for harvesting medicinal and magical herbs. The coincidence of the plant’s full flowering with the religious feast day solidified the connection. This timing was seen as a sign of the plant’s special power. The practice of gathering the herb on June 24th to ensure its maximum potency cemented the association with St. John the Baptist.
Understanding the Term Wort
The second element of the name, “wort,” is a linguistic key to understanding old English plant nomenclature. The term derives from the Old English word “wyrt,” which translates to “plant,” “herb,” or “root.” Historically, “wort” was commonly added to the names of herbaceous plants, particularly those recognized for having traditional medicinal properties.
This archaic suffix appears in the names of many unrelated plants, such as lungwort, liverwort, and spiderwort. The inclusion of “wort” in St. John’s Wort classifies the plant as “St. John’s herb.” The term’s persistence reflects a time before modern botanical classification, when plants were named for their perceived function or a defining characteristic.
Folklore and Naming Traditions
Beyond the calendrical association, the physical characteristics and folklore surrounding the plant reinforced its name. The yellow flowers of Hypericum perforatum have small, translucent oil glands on the leaves, which give the appearance of tiny punctures. These minute holes led to the species epithet perforatum and were often interpreted as the wounds of St. John.
When the flowers or buds are crushed, they exude a distinctive, dark red oil due to the presence of the compound hypericin. This red pigment was referred to in folklore as “St. John’s Blood,” connecting it to the martyrdom and beheading of the saint. This visual detail provided a powerful link to the saint’s story.
The plant also held a strong reputation as a protective herb, often called fuga daemonum, or “demon’s flight,” due to its traditional use in exorcisms and for warding off evil spirits. Historically, sprigs of the plant were hung over doors or religious icons to protect a dwelling from malevolent forces and lightning. This pre-Christian association with solar symbolism and protection was easily integrated into the Christian framework, securing the plant’s name and significance across centuries of cultural transition.