Information on Square-stalked St John's-wort

Common Name: Square-stalked St John's-wort
Scientific Name: Hypericum tetrapterum
Irish Name: Beathnua fireann
Family Group: Hypericaceae
Distribution: View Map (Courtesy of the BSBI)
Flowering Period


Click for list of all flowering by month
Square-stalked St John's-wort is not easily confused with other wild plants on this web site.


This perennial of the St John's-wort family can be identified by its distinctive square-stems which have definite wings.  The pale yellow five-petalled flowers (15 – 20 mm across) are borne in a flat-topped corymb on these stiffly erect stalks.  The flowers have pointed sepals which do not have any dots.  However, the oval leaves have translucent dots. This plant, which blooms from June to September, grows in damp ditches and marshy places.  It is a native plant belonging to the family Hypericaceae. 

I first identified this plant in Rath, Co Kerry in 1977 and photographed it in Gibletstown, Co Wexford in 2007. 

If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre

St John's-wort, Square-stalked
St John's-wort, Square-stalked

'A small weed called St Johns Wort is used for sore eyes.'

From the National Folklore Collection, University College Dublin. NFC 96:308  From Co Wexford