365 Urban Species. #177: St. Johnswort

Photos by cottonmanifesto. Location: Hillside of onramp between Jamaicaway and Perkin's street, Boston.

Urban species #177: St. Johnswort Hypericum perforatum

Much of the time during this project, I've been providing names to familiar plants of the city. Here I connect a familiar name to the plant. Most people have heard of St. John's Wort, the dietary supplement and herbal depression treatment. Here is the herb, an attractive if nondescript field weed, easily mistaken for goldenrod. It prefers sunny, well-drained areas; it does not compete well with other plants, but can be an effective colonizer of disturbed soils or recently burned areas.

St. Johnswort is a native of the Mediterranean, but has been brought around the world for its reputed herbal and magical properties. It was reputed to bloom on St. John's day--June 24th--and to repel evil spirits, witches (apparently this was Christian magic) and even lightning. These days the herb is used to repel depression; though one study emphasized that it is ineffective against major depression, it does seem to have an affect in treating minor to moderate cases. The active chemical, hypericin, has the side effect of making the patient sensitive to light. Livestock can also suffer from hypericin toxicity if they eat St. johnswort in pastures, developing sores on their faces. In the west, St. johnswort is considered a noxious weed because its presence contaminates forage crops in this way.