A native perennial with clusters of golden-yellow flowers, slender opposite leaves and rounded to egg-shaped seed capsules. Look closely at the unspotted petals and spreading stamens.
Family: Hypericaceae (St. John’s-wort)
Genus: Hypericum
Life cycle: Perennial; sometimes woody at the base
Height: Up to about 2½ feet
Bloom: June–August, depending on location
Light: Sun to partial sun
Habitats: Prairies, open woods, thickets, glades and disturbed open ground; moisture varies across its range. [1, 2]
Leaves: Opposite, smooth-edged and oblong to narrowly elliptic, tapering toward the base. The tips may be rounded or somewhat pointed.
Flowers: Five yellow petals surround numerous spreading stamens. Leaves and petals lack the conspicuous black spotting found in some other St. John’s-worts.
Fruit: Rounded to egg-shaped capsules narrow abruptly toward a short beak. Mature fruit helps confirm the identification. [1, 2]
Spotted St. John’s-wort: Look for dark dots and streaks embedded in the petals and leaves. Dark anthers at the ends of stamens are different from these glands.
Kalm’s St. John’s-wort: A woody shrub with narrower, often rolled-edged leaves and larger flowers containing a much denser mass of stamens.
Use several features together, including mature fruit and the lower stems, when comparing St. John’s-worts. [1, 4]
Native to southeastern Canada and the central and eastern United States, including Illinois and Wisconsin. It grows in a range of open habitats; Wisconsin records include wet prairies and moist disturbed sites, while Illinois habitats also include gravel prairies, glades and open woods. [1–3]
Observation maps show reported sightings, rather than the full native range.
