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.