Online Virtual Flora of Wisconsin

Hypericum ascyron L.

Family: Hypericaceae

giant St. John's-wort, great St. John's-wort

[Hypericum pyramidatum Aiton]

Merel R. Black

Emmet J. Judziewicz

University of Wisconsin-Stevens Point, Robert W. Freckmann Herbarium (UWSP)

Open Interactive Map

Etymology: Hypericum: ancient Greek name derived from hyper, "above," and eikon, "picture," from old practice of placing flowers above an image in the house to ward off evil spirits at the midsummer festival of Walpurgisnacht, which later became feast of St. John
Plants: robust, erect, perennial, 2'-5' tall forb branching near the top
Leaves: large, stalkless to clasping leaf drawing

Flowers: yellow, 5-parted, 1 1/2"-2 1/3" wide, long-stalked; usually solitary from the ends of the branches; blooms July-Aug.
Fruits: oval capsule with 5 chambers fruit drawing

Habitat: moist; woods, forests, openings, streambanks
Conservation Status: Native

Sedge meadows, marshes, fields, ditches, grassy areas along streams and rivers, low prairies, shaded talus slopes, wet cliffs, rock outcrops, along roadsides and railroads, and in mesic to wet forests of elm-basswood-hickory, maple-elm, red maple-green ash, aspen, aspen-black ash-mixed conifers, sugar maple, swamp white oak-ash-silver maple; especially on edges, along trails and logging roads, around ponds and seeps, and in meadows.

Our tallest species in the genus, sometimes reaching nearly 2 m. This species is also found in Asia and American plants are segregated as subsp. pyramidatum (Aiton) N. Robson.