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.