ID Guide - St John's Wort

    The St John's Wort (Hypericum) family are attractive, yellow-flowered perennials. They can look confusingly similar but can be distinguished by careful examination of key features. A hand-lens may be required (depending how good your eyesight is!).

    Species Stems Downy Flower dots Leaf dots Leaf perf
    Perforate  2 ridges   yes yes yes
    Trailing 2 ridges   yes yes yes
    Slender no ridges   yes no yes
    Hairy no ridges downy yes no yes
    Pale no ridges downy yes yes no
    Marsh no ridges downy no no yes
    Imperforate

    square

    unwinged

      yes yes no
    Square-stalked

    square

    winged

      no no yes

    The leaf perforations are visible as translucent dots if the leaf is held up to the light.