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.