Kalm St. Johns wort, is a small, dense, shrub or subshrub with upright branching that typically grows in a dense mound to 2-3’ tall. It is native to the Great Lakes region of the U.S. where it typically occurs in rocky to sandy soils, ranging from relatively dry open woods to moist lakeshore areas. Narrow, linear-oblong, stalkless, bluish-green leaves (to 2” long) in pairs on distinctive 4-angled stems are evergreen but some may drop in winter.
Five-petaled, golden yellow flowers (1.5-inch diameter) in 3- to 7-flowered cymes bloom in mid to late summer (July-August). Each flower has five styles and a distinctive center boss of yellow stamens. Flowers give way to beaked, oval, brown seed capsules that mature in fall and often persist on the shrub until spring. Leaves are dotted with tiny glands.