Plants of the Eloise Butler Wildflower Garden

There are a great number of St. Johnsworts in the genus Hypericum. The flowers are generally yellow and in terminal clusters. Great St. Johnswort is an erect native perennial plant that can reach to 5 feet in height with flowering branches near the top, unbranched below. Stems are multiple from the base, smooth and often reddish. See Eloise Butler's notes at the page bottom.

Leaves are opposite, large - lanceolate - and either stalkless or slightly clasping. The upper surface is a shiny green, margins are smooth.

The inflorescence is composed of mostly single flowers at the tops of many short terminal stems, and also rising from the upper leaf axils. Flowers are sometimes in a small cluster.

Flowers: Each flower is stout stemmed, the calyx with 5 green sepals that are smooth, with pointed tips and ovate bases and much shorter than the 5 yellow petals which have more rounded tips. These petals are often floppy looking or with contorted tips. Petals turn brown after pollination and remain in a twisted spiral instead of dropping. There are numerous stamens, united at their bases into 5 sets, each stamen with a yellow anther. The pistil is a yellow-green color, has 5 united carpels and 5 united styles which only separate at their tips. The styles persist onto the seed capsules. Flowers can be from 1.5 to 2.3 inches wide when open.

Seeds: The sepals remain, (along with the remains of the brown twisted petals) turning brown as the seed pod develops into an ovoid 5-celled capsule which contains several hundred small oblong brown seeds. Seeds require 60 days of cold stratification and then light for germination, so they should be surface sown.

Habitat: Great St. Johnswort grows from a rhizomatous root system, preferring full sun and wet-mesic to mesic moisture conditions. It tolerates some shade and will adapt to most soil types. Bumblebees are the primary pollinators. If forms clumps from the rhizomes rather than spreading colonies, and also re-seeds readily.

Names: Some references assign this plant as Hypericum ascyron in the family Clusiaceae. Neither that species name or that family is currently accepted by most authorities including the U of M Herbarium on their Checklist of the Vascular Flora of Minnesota (Ref.#28C) The genus Hypericum is from the Greek hyperikon, meaning 'above picture' or 'above an apparition' and refers to the old practice of placing a sprig of a Hypericum above images or in the house to ward off evil at such times as the during the old festival of Walpurgisnacht and especially on midsummer eve, the night before St. John's Day. (see next paragraph). The species pyramidatum means 'pyramid shaped' which is the shape of the flower buds and the seed capsules of this species. The author name for the plant classification, ‘Aiton,’ is for William Aiton (1731-1793), Scottish botanist, succeeded Philip Miller as superintendent of the Chelsea Physic Garden and then became director of Kew Gardens, where he published Hortus Kewensis, the Garden’s catalogue of plants.

The common name of 'St. Johnswort' is a European reference to St. John's Day, a church feast date on June 24th when the plant would usually be in flower; the 'wort' portion referring to the plants healing properties. These properties refer to the European species Hypericum perforatum which was brought to the New World and now widely spread. The eve of St. John's Day (San Giovanni in Italy), midsummer eve, June 23rd, is considered a night for spirits and witches. It is several days after the actual Summer solstice date but is a remnant of the old Julian calendar.

Comparisons: Common St. Johnswort, Hypericum perforatum, is not native and the leaves are different as is the flower structure.