St John’s wort is a perennial plant with extensive, creeping rhizomes. Its stems are erect, branched in the upper section, and can grow to 3 feet high. It has opposing, stalkless, narrow, oblong leaves that are 1/2″ inch long or slightly larger. The leaves are yellow-green in color, with transparent dots throughout the tissue and occasionally with a few black dots on the lower surface. Leaves exhibit obvious translucent dots when held up to the light, giving them a âperforatedâ appearance, hence the plant’s Latin name.
Its flowers measure up to 1″ across, have five petals, and are colored bright yellow with conspicuous black dots. The flowers appear in broad cymes at the ends of the upper branches, between late Spring and early to mid Summer. The sepals are pointed, with glandular dots in the tissue. There are many stamens, which are united at the base into three bundles.
When flower buds (not the flowers themselves) or seed pods are crushed, a reddish/purple liquid is produced.