A small native wetland wildflower with tiny yellow blooms and opposite, rounded leaves. Look for leaflike bracts among the flowers and rounded capsules that extend beyond their sepals. [1]
Northern St. John’s-wort in flower. Select the photograph to enlarge. Photograph: Where’s Wildlife.
Family Hypericaceae
Life cycle Perennial
Blooms July–September (Upper Midwest)
Height About 4–16 inches
Light & habitat Sun to partial shade; wet sandy or mucky ground
Common name
Northern St. John’s-wort
Size and flowering time vary with conditions. [1, 2]
Explore photographed sightings and their locations.
Leaves: Smooth-edged, stalkless blades grow in opposite pairs. Their tips are usually rounded.
Flowers: Five yellow petals surround a small group of stamens. Blooms are only about 3–5 mm wide.
Bracts: Small leaflike blades accompany the flowers. [1, 2]
Search wet shorelines, pond margins, marshes, bogs and streambanks. This low plant can be easy to overlook among taller vegetation. In the Upper Midwest, look for flowers from July through September. [2]
Dwarf St. John’s-wort (Hypericum mutilum) has tiny, narrow flower bracts that differ from its leaves. Northern has leaflike bracts. Compare mature fruits too: Northern’s blunt sepals are shorter than its capsules; Dwarf’s sepals are about as long as the capsule. [1]
Include leaves, branching stems and the small blades immediately below the flowers. These views provide more identification clues than flower color alone.
The petals lack the conspicuous black dots seen in Spotted St. John’s-wort. A close view also reveals relatively few stamens rather than a dense brush of them. [1, 2]
After flowering, small oval capsules develop and may turn reddish purple. Compare the rounded fruit tip with the shorter sepals around its base. [1, 2]
Native to northern and eastern parts of North America, including the Great Lakes region. It is also introduced in some western areas. [1, 2]
Some references use the synonym Hypericum mutilum subsp. boreale. Here it is treated as Hypericum boreale.
Reported observations help locate photographed plants; they do not define the complete native range.
Distribution: Kew Plants of the World Online.
Observations show reported sightings; they do not define the plant’s complete native range.
Compare Northern, Spotted, Common, Kalm’s and Giant St. John’s-worts, then practice in the wildflower quiz.
