Shrub to 2 m tall Leaves: opposite, short-stalked, 3 - 6 cm long, 0.8 - 1.5 cm wide, linear to oblong or narrow elliptic with an abruptly tapered base, non-toothed. Smaller leaves are borne in the axils of larger leaves. Flowers: borne three to seven on a small widely branched terminal inflorescence (cyme) with smaller clusters (cymules) in the upper leaf axils. The 2 - 3 mm wide sepals are lance- to egg-shaped with a pointed tip, the five yellow petals are 7 - 10 mm long, the stamens are numerous, and the four styles are attached near the base. Fruit: a three-chambered capsule, 0.7 - 1.4 cm long, 3.5 mm wide, cone- to egg-shaped, beaked, with chambers partitioned but not joined at the center. The capsules persist throughout winter. Bark: gray and thin, shedding to reveal pale orange inner bark. Twigs: stiff, erect, reddish brown, becoming gray to light brown with age, highly branched, two-edged (sharper when young).
Similar species: Hypericum prolificum and Hypericum kalmianum are the only shrubby Hypericum species in the Chicago Region. Hypericum kalmianum reaches 1 m tall, has peeling papery white to multicolored bark, four-angled twigs, leaves less than 8 mm wide, flowers with 10 - 16 mm petals and five styles, and five-chambered capsules.
Flowering: June to September
Habitat and ecology: Local in partial shade along stream edges, brushy prairies, and railroads.
Occurence in the Chicago region: native
Notes: This species makes a nice native ornamental shrub. Bees collect nectar from the flowers.
Etymology: Hypericum is the Greek name for St. John's Wort, which blooms around St. John's Day (June 24). Prolificum means abundant, referring to the many stamens.
Author: The Morton Arboretum
From Flora of Indiana (1940) by Charles C. Deam
Throughout the state although it seems to be rare or absent about Lake Michigan. In moist soil, usually in woods, along streams, and about swamps. More rarely in dry or moist soil along roadsides and on wooded slopes. It was noted in Crawford and Martin Counties where it had abundantly invaded abandoned fields. I also saw it in crevices of sandstone of a high cliff in Crawford County.
Diffusely branched shrub to 2 m, the twigs sharply 2-edged; lvs articulate at the base, linear to oblong or narrowly elliptic, 3-6 cm נ4-15 mm, usually abruptly narrowed to a short petiole; infl a small terminal cyme of mostly 3-7 fls, often with additional cymules from the upper axils; pet 7-10 mm; styles 3(4), connate at the base and forming a beak on the fr; fr mostly 7-14 mm, quasi- 3(4)- locular, the partitions meeting in the center but not joined; 2n=18. Many habitats, from swamp-margins to cliffs and woods; N.Y. to s. Mich. and Minn., s. to Ga. and La. July-Sept. (H. spathulatum)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.